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Tutorial 9: MPEG-4 and H.264/AVC buffer analysis

Figure 70: Graph details

18.

Note the following details about the graph:

The Y scale of the graph is locked, which keeps the graph at a useful

zoom level.

The VBV graph is higher at the end of every frame than at the start, which

shows that the VBV buffer is

lling faster than the decoder can empty it.

19.

Click the

icon to zoom out.

20.

Select the

Use custom parameters

option button. (See Figure 71.) The word

BUF

appears in a yellow box in the main MTS4EA status bar, indicating that

custom buffer parameters are in use. (See Figure 72.)

MTS4EAV7 HEVC / AVC Video and Compressed Audio Analyzer Tutorials

Содержание MTS4EAV7

Страница 1: ...xx MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer ZZZ Tutorials P001165001 001 1650 01 ...

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Страница 3: ...MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer ZZZ Tutorials xx www tektronix com 001 1650 01 ...

Страница 4: ...d and pending Information in this publication supersedes that in all previously published material Specifications and price change privileges reserved TEKTRONIX and TEK are registered trademarks of Tektronix Inc Contacting Tektronix Tektronix Inc 14150 SW Karl Braun Drive P O Box 500 Beaverton OR 97077 USA For product information sales service and technical support In North America call 1 800 833 ...

Страница 5: ...ce basics 31 Procedure 31 Conclusion 36 Tutorial 6 MP4 optimization 37 Procedure 37 Conclusion 41 Tutorial 7 3GPP MPEG 4 compliance 42 Procedure 43 Conclusion 47 Tutorial 8 H 264 AVC syntax error 48 Procedure 48 Conclusion 50 Tutorial 9 MPEG 4 and H 264 AVC buffer analysis 52 Procedure 53 Conclusion 64 Tutorial 10 MPEG 2 compliance 65 Procedure 65 Conclusion 74 Tutorial 11 Fidelity analysis 75 Pro...

Страница 6: ...Table of Contents Tutorial 13 Closed caption and AFD analysis 97 Procedure 98 Conclusion 105 ii MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 7: ...your codec software give the best reductions in bits used for the least reduction in visual quality What types of video content does your codec work poorly with and why A description for each tutorial follows See Table 1 Table 1 Tutorial descriptions Tutorial Name Standard Areas Covered 1 H 261 H 261 Syntax error compression optimization graph analysis 2 H 263 compliance and motion vectors H 263 B...

Страница 8: ... complete the tutorial procedures you must be familiar with the following basic functions See Table 2 To perform the desired function click the associated icon or type the appropriate keyboard shortcut Table 2 Basic functions Function Forward Backward Icon Keyboard shortcut Icon Keyboard shortcut Play video Ctrl P Ctrl Shift P Stop video Ctrl S Ctrl S Pause step one frame Ctrl A Ctrl Shift A Fast ...

Страница 9: ...tates that the temporal reference TR value is the previous TR value 1 the number of skipped or non reference pictures at the picture clock frequency PCF TR is 8 bits only 0 255 at the standard PCF of 29 97 frames per second However if a custom PCF is used then TR is 10 bits 8 LSBs are denoted as TR and 2 MSBs are ETR but they are taken together as a single 10 bit number 2 View the warning message ...

Страница 10: ...the following See Figure 2 Movement in the video is too quick requires PC with processing speed of greater than or equal to 1 GHz Unwanted noise visual artifacts is visible when the man waves his arm starting around frame 128 continuing into frame 161 with some artifacts remaining until frame 203 Status bar notes that one alert is disabled Although the video stream will play and will probably be d...

Страница 11: ...igure 3 MB overlay 7 Check that the video is in either Play or Pause mode 8 Click the MB Tooltip icon on the toolbar The Tooltip typically docks at the left edge of the window but you can undock it by pressing CTRL on your keyboard while dragging the Tooltip with your mouse 9 Move the mouse over the video A white box will display around the MB from which data is being read The Tooltip shows inform...

Страница 12: ...round wall These block types use the most bits See Figure 5 Figure 5 Intra MBs in the background wall and MB data 11 Stop the video sequence 12 To analyze the MB data select Analysis from the menu and select Video graph enable A dialog box will appear See Figure 6 6 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 13: ...the output filename h261 xls 15 Click OK and then play the video 16 When play ends the data is exported to the xls file and MS Excel will open Click Enable macros The screen will flash as the macros run 17 Click Spatial Bits per MB to view a graph of the spatial bits per MB See Figure 7 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 7 ...

Страница 14: ...are used in the center by the man top left too many and along the bottom edge too many These last two are errors 18 Click the Intra Coded Frequency tab to view a graph of the Intra Coded Frequency See Figure 8 8 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 15: ...th Intra coding in the encoder Conclusion This tutorial demonstrated that the H 261 bitstream is not standard compliant and that there were coding inefficiencies These problems were discovered through TR errors and frequency of playing Coding inefficiencies were discovered through graphical analysis MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 9 ...

Страница 16: ...re 1 To load the H 263 tutorial click File Example files H 263 stream Rally 250K The window title changes to MTS4EA H 263 Example Rally 250k and a warning message appears See Figure 9 Figure 9 Initial warning message 2 View the warning message elements Warning Indicates that the PSUPP field is being sent and ignored Summary Gives summary information about the stream 10 MTS4EAV7 HEVC AVC Video and ...

Страница 17: ... or type CTRL P to resume playing the video Another error message appears See Figure 10 5 View the error information provided which indicates a more serious error that occurs at bitstream byte address 0x0c9cfa bit 3 after frame 326 Figure 10 Initial error message 6 Click Continue Another error message will appear See Figure 11 7 Note that it was an MBCPC error that resulted in the Out of Sync aler...

Страница 18: ... Alert log window will appear See Figure 12 10 Note the active filter button in the toolbar Because Skip ALL error alerts in the future was selected the alert log view is filtered and the filter button is active The status bar indicates that 23 of 24 alerts are hidden 11 Click the Filter icon to deactivate the filter and view all alerts See Figure 13 12 MTS4EAV7 HEVC AVC Video and Compressed Audio...

Страница 19: ...Tutorial 2 H 263 compliance and motion vectors Figure 12 Alert Log window filtered Figure 13 Alert Log and Alert Details MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 13 ...

Страница 20: ... bitstream Details Alert details Figure 14 Alert Log unfiltered 13 Close the Alert log and return to the main page of the application 14 Click the icon to play the video again with the Motion Vectors MVs visible See Figure 15 15 Note the following about the image The white dots are at the center of each MacroBlock The white lines indicate motion vectors The arrows for each MV point to the position...

Страница 21: ...usion This tutorial demonstrated where there is a standards compliance issue in the H 263 bitstream but also showed that other aspects of the H 263 bitstream such as the motion vectors are implemented properly MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 15 ...

Страница 22: ...bitstream byte address 0x11 bit 3 before VOP 1 The error is present in the header and MTS4EA does an initial check of the file header when it loads the file The error indicates that method 1 quantization is in use which is not allowed because the stream is Simple Profile 3 Click Continue MTS4EA loads the stream and the window title changes to MTS4EA MPEG4 Example Space 4 Click the icon or type CTR...

Страница 23: ...en click Hex See Figure 17 The Hex view appears with the error location highlighted See Figure 18 7 Close the Hex view and again view the initial error shown message The error occurs because modulo_time_base was set to 1 after a whole second elapsed MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 17 ...

Страница 24: ...ure 18 Hex view with error location 11 From the Overlay menu click Video summary tooltip to enable the Video Summary tooltip 12 View the Final Video Summary Tooltip and note these field descriptions See Figure 19 Image size 352 pixels high x 288 pixels wide CIF Stream size 976 kBytes Total frames 175 Total play time of the sequence 13 920 seconds Total bits 7 998 576 Bandwidth required to transmit...

Страница 25: ...inal video summary tooltip 14 To see if the codec makes the best use of the MPEG 4 standard open the Overlay menu and then click MB Types you can also type CTRL Y The MB Types key appears 15 Move forward 3 frames The MB types are color coded See Figure 20 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 19 ...

Страница 26: ...e 22 18 Go back to frame 34 19 From the Overlay menu click MB Statistics and then click Bits Note that the black background uses a high number of bits See Figure 23 20 View frames 35 36 and 37 and observe that the background uses progressively fewer bits See Figure 24 21 Compare frame 34 with frame 37 Observe that the black background in frame 34 is coded and uses many bits while the black backgro...

Страница 27: ...Tutorial 3 MPEG 4 compliance Figure 21 Frame 34 color key Figure 22 Frames 35 36 and 37 color key Figure 23 Frame 34 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 21 ...

Страница 28: ...which wastes many bits Consider whether there are software bugs such that the encoder is too sensitive to minor changes in the gray level Check the encoder part of the codec that decides when to use Intra MBs and Inter MBs and when to not code the MB Fixing this problem would save many wasted data bits NOTE The MPEG 4 standard provides more data bits for intensity gray level than for color informa...

Страница 29: ...interpret the alert messages Use the Video summary tooltip and understand the provided information Use the MacroBlock overlays MB types and motion vectors Use the MacroBlock and Summary tooltips Use the hexview bitstream viewer View Trace files Parse bitstream and interpret Procedure 1 To load the MPEG 4 tutorial click File Example files MPEG 4 Elementary streams Window Car A stuffing_bits error o...

Страница 30: ...ue when the VCV overflow alert appears See Figure 26 Figure 26 VCV overflow alert 4 Click the Video Navigator icon The Video Navigator window will appear in either Detail See Figure 27 or Thumbnail view See Figure 28 Figure 27 Video Navigator window detail view 24 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 31: ...ting Tile Horizontally on the Window menu to view the tiles horizontally The following views can also be synchronized Buffer analysis HexView Alert log Fidelity analysis Trace Parse bitstream and Trace Interpret Figure 29 Horizontal view 6 Click the synchronize views icon See Figure 30 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 25 ...

Страница 32: ... navigator and the video views are synchronized 8 Click the icon at the top left corner of the video navigator window to see the thumbnail view Each thumbnail is labeled with the frame type display frame number and the display time in seconds See Figure 31 26 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 33: ...t frame should now be displayed in the video window 9 Double click on frame 57 Decoding restarts from the beginning and stops at frame 57 See Figure 32 Figure 32 Synced navigator and video window views of frame 57 and frame 51 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 27 ...

Страница 34: ...pret from the drop down menu View the Trace files frames 1 3 An alert will appear See Figure 33 Figure 33 Trace files warning frames 1 3 NOTE Warnings errors and fatals are always shown in the Trace Parse bitstream and Trace Interpret files whether or not the pop up alerts are enabled 12 In the Trace Interpret window select the address 0x00000009 1 and right click Select Goto view and then Hex The...

Страница 35: ...ch for items using as a wildcard character For example you can enter the start code 0001b to find 0001b1 0001b5 and 0001b6 See Figure 35 Figure 35 HexView window 14 Save your setup by clicking File and then selecting Save project You can change the filename See Figure 36 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 29 ...

Страница 36: ...drop down menu An alert will pop up when the video file is loaded Dismiss it by selecting Skip this and Continue See Figure 37 Figure 37 Opening the project file Conclusion This tutorial demonstrated how to View different video data and navigate between different views Store setups Identify stuffed bit errors 30 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 37: ...hexview bitstream viewer Procedure 1 To load the MP4 tutorial click File Example files MP4 Files Packet Woman A list of tracks included in the MP4 appears in a dialog box See Figure 38 2 View the track information included in the dialog box The video track ID for example is 001 Although there can be multiple tracks the first video track is selected automatically 3 Click OK The video track is analy...

Страница 38: ...Tutorial 5 MP4 compliance basics Figure 38 Track list Figure 39 Initial error message 32 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 39: ...as a limit of 396 MBs Figure 40 VCV overflow warning message 7 Select Skip this Warning only in the future and then click Continue Another buffer conformance warning message appears See Figure 41 8 Select Skip this Warning only in the future and then click Continue 9 To ensure that the application window is active click the Title bar 10 From the analysis menu select View video stream structure The...

Страница 40: ...e 42 Structure window 12 From the File menu click Close stream and then reopen the stream 13 When the track list appears click Extract See Figure 43 The Save stream file as dialog box appears See Figure 44 34 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 41: ...t file name if required The track ID and video file type has been automatically appended to the file name NOTE To open this dialog box in the future for a video track that was not extracted at the time the MP4 file was first opened open the File menu and then click Save stream file as MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 35 ...

Страница 42: ...ew the tracks in an MP4 file Extract and play a video while checking for errors Identify and locate the Level conformance error Identify two buffer conformance errors see Tutorial 5 for details about buffer analysis 36 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 43: ...MB types and motion vectors Use the hexview bitstream viewer Open MP4 files view extract the video and view the MP4 file structure Procedure 1 To load the MP4 tutorial click File Example files MP4 Files Picadilly Circus A list of tracks included in the MP4 appears in a dialog box See Figure 45 2 View the track information included in the dialog box The video track ID for example is 001 Although th...

Страница 44: ...ip this Warning only in the future and then click Continue 8 View the progression of frames and note that the first frame is green as is every third frame Intra MBs See Figure 47 Another buffer conformance warning message appears See Figure 48 38 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 45: ... VBV underflow warning 9 Select Skip this Warning only in the future and then click Continue 10 To replay the video file click Pause step forward Note that the first frame takes 32 456 bits See Figure 49 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 39 ...

Страница 46: ... twice to reopen the MB Types Key window 13 To undock the MB Types Key window hold the CTRL key while dragging it with the mouse pointer 14 View the next six frames including Frame 2 See Figure 50 15 For each frame view the details which are outlined in Table 3 40 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 47: ...sion This tutorial demonstrated the following The I VOPs require about 4 5 times as many bits as the P VOPs There are I VOPs every 3rd frame There is no need to have I VOPs so often If the frequency of I VOPs were reduced to 1 in 30 the bits used for the sequence would reduce by 45 You can reduce the number of bits used MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 41 ...

Страница 48: ...environment This tutorial requires that you have completed the previous tutorials and that you know how to Play stop step forward and fast forward the video Use and interpret the pop up alerts Use the Video summary tooltip and understand the information provided Use the MacroBlock overlays MB types and motion vectors Use the hexview bitstream viewer Open MP4 files view extract the video and view t...

Страница 49: ... appears in a dialog box The first video track is automatically selected See Figure 51 Figure 51 3GPP track list 2 Click OK 3 An alert will appear for a syntax error This error shows as a reserved value 0 for profile_and_level_indication See Figure 52 4 Click Continue and do not enable Skip MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 43 ...

Страница 50: ...rame 1 and look at the error at address 4 bit 7 See Figure 53 Figure 53 Trace Interpret error at address 4 bit 7 6 Play the video again and at the error click Goto and then select Hex from the drop down menu See Figure 54 44 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 51: ...rror locations highlighted 8 To look at the VOP types first stop the stream if it is playing 9 Click the Summary tooltip icon to turn on the tooltip 10 Click the MB Types Overlay icon to turn on the overlay 11 Play or Pause Step forward through the sequence to the end Notice that the first frame and every second frame are Intra MBs See Figure 56 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyze...

Страница 52: ...tip on again if it is not already on 13 Click the Pause Step Forward icon to move to frame 1 14 Notice in the Summary window that resync markers and data partitioning are both on This is vital for good error resilience in a mobile environment See Figure 57 Figure 57 Summary window data 46 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 53: ...ltip allows you to look at VOP types Reducing the frequency of I VOPs can allow for better quality video in the same bit rate With error resilience tools in use the frequency of I VOPs can be reduced reducing the bit rate by approximately 15 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 47 ...

Страница 54: ...e Interpret Procedure 1 To load the tutorial click File Example files H 264 AVC Byte Streams Canary Wharf 2 An incorrect direct_8x8_inference_flag error will occur at address 0x0 bit 7 when the file is loaded See Figure 58 Figure 58 Direct_8x8_inference_flag error alert 3 Notice that the syntax error occurs before frame 1 This is the displayed frame number Check the Skip this box and then click Co...

Страница 55: ...t ID error 5 Click on Analysis in the menu Select Trace enable and then select Frame range from the drop down menu 6 Set the frame range from 1 to 2 This will run the Trace Interpret and Trace Parse bitstream on frames 1 and 2 7 View the Trace file and clear the Frame box Click Find Next three times An error alert will appear See Figure 60 Figure 60 Trace Parse bitstream error MTS4EAV7 HEVC AVC Vi...

Страница 56: ...window and type pic_parameter_set_id in the text box 11 Click Find Prev to search for an occurrence of pic_parameter_set_id before the error Note that it does not occur before the location of the PPS ID error at 0x1c 7 See Figure 62 Figure 62 Pic_parameter_set_id error location search Conclusion This tutorial demonstrated the following The pic_parameter_set_id 1 did not occur before the slice head...

Страница 57: ... from the last known good pic_parameter_Set_id ID 0 and continues decoding NOTE This may not always be possible and could generate other consequential errors THE MTS4EA showed what the error was and where it occurred MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 51 ...

Страница 58: ...e alert messages This tutorial also requires that you already understand the principles of buffer analysis conformance VBV VCV VMV in MPEG 4 and H 264 AVC HRD The following table provides the functions of each Buffer Analysis toolbar icon See Table 4 Table 4 Buffer analysis icons Icon Function Zoom in and zoom out centered on the window affected by the Lock X Y icons Fit all data into window Go to...

Страница 59: ...the Lock X Y icons Zoom in zoom out centered on the location of this cursor this is affected by the Lock X Y icons Press the shift key to zoom out Procedure 1 To load the tutorial click File Example files MPEG 4 Elementary Streams Man Walking Ensure that the video is not playing 2 From the Analysis menu click View buffer analysis The Buffer Analysis window appears See Figure 63 3 View the buffer a...

Страница 60: ...ar beside the graph See Figure 64 These parameters are specified in the stream or from the implied values from the Profile Level as given in the standard or the implied values from the Object Type Simple or Advanced Simple at the highest level for each You can enter them manually by selecting Use custom parameters Figure 64 VBV VCV and VMV values 5 Click the Pause Step Forward icon three times Not...

Страница 61: ...ew of the graph See Figure 65 8 Click the Fast forward icon A warning message occurs See Figure 66 9 Note that the VBV overflow occured while decoding frame 55 the display frame number is 54 Figure 65 Buffer analysis graph detailed view MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 55 ...

Страница 62: ...goes above the Buffer limit line See Figure 67 12 Observe that when the decoding stops the graph looks like the section that appears between 75 and 105 buffer occupancy Note also that the number of frames with VBV overflow appears at the bottom of the screen In this case the number of frames with VBV overflow is 106 56 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 63: ...r analysis Figure 67 Buffer limit graph 13 To fit the graph to the window click the icon on the Buffer Analysis toolbar The red line displays the VBV overflow See Figure 68 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 57 ...

Страница 64: ...s the rate at which the encoder sends the data to the decoder Increase the displayed frame rate so that the decoder removes bits more quickly Increase the number of bits per frame by changing the quantizer or increasing the frame size Change the Profile Level indication so that it stays within the set limits for example change to ASP at Level 2 Use custom values in the vbv_parameters in the sequen...

Страница 65: ...has disappeared because it is beyond the scale set for the VBV 17 Click the icon on the Buffer Analysis toolbar and then click the icon three times for a detailed view of the graph See Figure 70 Figure 69 Frame 2 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 59 ...

Страница 66: ...er at the end of every frame than at the start which shows that the VBV buffer is filling faster than the decoder can empty it 19 Click the icon to zoom out 20 Select the Use custom parameters option button See Figure 71 The word BUF appears in a yellow box in the main MTS4EA status bar indicating that custom buffer parameters are in use See Figure 72 60 MTS4EAV7 HEVC AVC Video and Compressed Audi...

Страница 67: ...r verifier See Figure 73 The default vbv_buffer_size for ASP L0 is 163 840 bits 20 480 bytes which is not very large 22 Enter 655 360 bits 80 kbytes click Apply and then click the Fit to window icon Observe that the graph stays below the limit and there are no overflows or underflows MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 61 ...

Страница 68: ...hich your device will operate Figure 73 Video buffer verifier graph 24 Reset the parameters by clicking Use parameters from stream header and then reselect the Use custom parameters check box The VBV graph shows that the decoder is being supplied with data faster than it can decode 25 Reduce the bit rate to 121072 bits and then click Apply See Figure 74 The graph goes up slightly and there are few...

Страница 69: ...r graph 26 Reduce the bit rate to 111072 bits and then click Apply See Figure 76 27 Observe that the graph line now stays below the buffer limit See Figure 77 28 Consider whether the maximum rate of 111 072 bits meets your network s specifications MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 63 ...

Страница 70: ... 4 example Man Walking showed that the stream does not comply with the buffer constraints The tutorial recommended ways to resolve this issue The tutorial also brought up the following considerations How much memory needs to be allocated Can your hardware allow this much memory usage Is the input data rate limit appropriate for your network 64 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer ...

Страница 71: ... bitstream in the HexView Looking at the MPEG 2 program stream structure Looking at MacroBlock types in an interlaced video Procedure 1 To load this tutorial click File Example files MPEG 2 Program Streams Person Track A list of tracks included in the MPEG 2 program stream appears in a dialog box See Figure 78 2 View the track information included in the dialog box The video track ID for example i...

Страница 72: ...9 4 View the error message details which provide a summary of the stream up to the point of the error 5 Click Continue Ensure that the Skip this Error only in the future check box is not selected Another buffer conformance error message appears See Figure 80 66 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 73: ...dct_differential field at bitstream byte address 0x1000 bit 5 7 Click Continue Ensure that the Skip this Error only in the future check box is not selected Repeat this step for an additional error message that appears 8 Resume playing the video Observe that the error is visible in frame 1 See Figure 81 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 67 ...

Страница 74: ... VLC error message appears See Figure 82 11 From the Goto menu click Hex 12 Click Continue and then view the HexView window Note that the error is highlighted automatically See Figure 83 13 Observe the bits surrounding the error and consider whether it is a start code emulation 68 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 75: ...rror message Figure 83 HexView window 14 To open the Grenadier Guards program stream Click File Example files MPEG 2 Program Streams Grenadier Guards An error message appears See Figure 84 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 69 ...

Страница 76: ...or only in the future and then click Continue The status bar indicates one disabled alert See Figure 85 An error message See Figure 86 and a warning message See Figure 87 appear Figure 85 Disabled alert indicator 17 For both error messages select Skip this Error or Warning in the future and then click Continue Do not resume playing the video 70 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer...

Страница 77: ... From the Analysis menu select View video stream structure The Structure window appears See Figure 88 19 View the top level atoms in the MPEG 2 program stream Click the next to each atom to view the data for the atom MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 71 ...

Страница 78: ...oolbar appears See Figure 89 Figure 89 Interlace toolbar 21 Click the Pause Step Forward icon to view frame 2 22 On the Interlace toolbar click the Split fields view icon The top and bottom fields are displayed separately See Figure 90 72 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 79: ...ce Figure 90 Frame 2 23 Maximize the video window 24 Click the icon Different MB types appear in the top and bottom fields See Figure 91 Figure 91 Varied MB types MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 73 ...

Страница 80: ... the visual quality There are two errors and one warning message in the Grenadier Guards stream The errors are in the header before frame 1 at bitstream location 0x15 bit start 6 The warning message highlights the same error This does not appear to affect the visual quality You can see the different MacroBlock types in the top and bottom fields 74 MTS4EAV7 HEVC AVC Video and Compressed Audio Analy...

Страница 81: ...he buffer analysis graphical display This tutorial also requires that you already understand the principles of fidelity analysis this topic is not covered in this tutorial however the user manual contains descriptions of the fidelity metrics Procedure 1 To load the tutorial click File Example files MPEG 4 Elementary Streams Man Walking Ensure that the video is not playing 2 From the Analysis menu ...

Страница 82: ...om the Analysis menu click Enable fidelity trace 6 On the Trace tab select the Enable check box choose the filename mp4asp_1_video and then under Options select VOP Fidelity See Figure 93 7 On the Frame range tab select the All frames check box and then click OK The video window appears with the fidelity analysis icon enabled in the Views toolbar See Figure 94 76 MTS4EAV7 HEVC AVC Video and Compre...

Страница 83: ...tab 8 Click the Fidelity analysis icon The Fidelity analysis graph view appears Observe that the graph is empty because a video has not been played See Figure 95 9 Click the icon four times A graph appears See Figure 96 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 77 ...

Страница 84: ...d Some of the YUV PSNR values are not visible This is because the graph auto scales with the first few values You can click the icon to rescale the graph The thumbnail bar view shows that the fidelity data has been collected 11 View the descriptions of the Fidelity analysis window in the figure and the table See Figure 97 See Table 6 Figure 95 Fidelity analysis graph 78 MTS4EAV7 HEVC AVC Video and...

Страница 85: ...Tutorial 11 Fidelity analysis Figure 96 Fidelity analysis graph MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 79 ...

Страница 86: ...6 Thumbnail bar line displays overview 7 Vertical blue line at time 0 vertical gray lines at each VOP decode time 8 Frame type number 9 Graph window control toolbar 12 To open the Grenadier Guards program stream Click File Example files MPEG 2 Program Streams Grenadier Guards An error message appears 13 Select Skip this Error only in the future and then click Continue 14 From the Analysis menu sel...

Страница 87: ...lick OK and then view the graph result See Figure 98 17 Load the MPEG 2 program stream example Grenadier Guards See Figure 99 18 Compare the first MPEG 2 program stream with the H 264 AVC PSNR example See Figure 99 See Figure 100 Note that the PSNR is higher for H 264 AVC in Y U and V Figure 98 Graph result YUV frame rate 25 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 81 ...

Страница 88: ...lity analysis Figure 99 MPEG 2 program stream Grenadier Guards Figure 100 H 264 AVC stream Grenadier Guards 19 Click the View trace icon See Figure 101 82 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 89: ...other fidelity analyses do the same kinds of differences occur Although the PSNR is better for the H 264 AVC sequence it does not necessarily look better Consider the visual differences Figure 102 H 264 AVC sequence 22 Load the MPEG 2 stream Grenadier Guards 23 From the Overlay menu click Visual difference and then select the Enable check box 24 Set the Frame rate to 25 and then click OK The Visua...

Страница 90: ...hod for assessing visual quality through The use of metrics such as PSNR Identifying the visual difference between the encoded video and the reference source video that is used for the encoding Visual quality analysis and visual quality improvement require that you consider encoding parameters such as frame types and motion vectors and bit rates of encoding This tutorial provided the tools to help...

Страница 91: ...video Use and interpret alert pop up messages Use the icons and controls on the buffer analysis graphical display Procedure 1 To load the tutorial click File Example files HEVC Byte Streams Forbidden City 2 As the stream is recognized as H 265 HEVC and opened in the Video View the HEVC tooltips are enabled Figure 103 HEVC tooltips 3 Click the Pause the stream or step forward on frame button to sta...

Страница 92: ...color grids show the Prediction unit partitions in the selected CTU Figure 104 CTU and CU tooltips for HEVC streams 6 Use the wheel on the mouse to zoom in on a CTU when the size is too small to view the individual CUs Click different CUs within a CTU to view the parameters of each CU 7 Click another portion of the video to observe that the tooltips update the CTU and CU statistics respectively fo...

Страница 93: ...ified to indicate the CU Type The colors used are displayed in the CU types key tooltip The CUs that are displayed grey implies that they are skipped Skip flag true this can be checked in the Coding Unit tooltip The grid lines shown below are displayed only when the video is either in pause or stop mode In all other modes only the CU overlay colors are displayed Figure 105 Coding Unit type CU tool...

Страница 94: ...s modified to indicate the PU Type The colors used are displayed in the PU key tooltip The PUs that are displayed grey implies that they are skipped Skip flag true this can be checked in the Coding Unit tooltip The grid lines shown below are displayed only when the video is either in pause or stop mode In all other modes only the PU overlay colors are displayed Figure 106 Partition type PU tooltip...

Страница 95: ...izes 4x4 8x8 etc The colors used are displayed onscreen in the TU types color key tooltip TUs that are displayed grey imply that they are skipped Skip flag true this can be checked in the Coding Unit tooltip The grid lines shown below are displayed only when the video is either in pause or stop mode In all other modes only the TU overlay colors are displayed Figure 107 Luma Transform Unit TU toolt...

Страница 96: ...are displayed grey imply that they are skipped Skip flag true this can be checked in the Coding Unit tooltip The grid lines shown below are displayed only when the video is either in pause or stop mode In all other modes only the TU overlay colors are displayed In the case of a Chroma TU a 8x8 CU can be colored yellow completely marking 4x4 as per color key tooltip This implies that only a 4x4 reg...

Страница 97: ...ltip does not show any slice boundaries The number of slices in the frame can be found from the Number of slices field in the Video frame summary tooltip Slice grids are available even while the video is being played unlike the CU PU and TU tooltips Figure 109 Slice partitions tooltip for HEVC streams MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 91 ...

Страница 98: ...he Tile tooltip does not put up any tile boundary The number of tiles in the frame can be found from the Number of tiles field in the Video frame summary tooltip Tile grids are available even while the video is being played unlike the CU PU and TU tooltips Figure 110 Tile partitions tooltip for HEVC streams 92 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 99: ... size types 16 At this point in the tutorial you are viewing only the first frame in the Video View Therefore the graph initially shows only the CU sizes for the first frame Click the Pause the stream or step forward on frame button a couple of times to advance the HEVC analysis frame by frame As shown below the graph fills in data for each frame as you advance the video Figure 111 CU Size Distrib...

Страница 100: ...ded Predicted or Residual 19 Select Residual from the drop down list to display the residual video information in the Video View Figure 112 Residual display in the Video View 20 Select Decoded from the drop down list to return the Video View to the decoded video information display 94 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 101: ... View select colors and numbers to see the bits allocation for the given frame per CTU Figure 113 CTU bits statistics display in the Video View 23 Select the mouse Zoom in and out function wheel to navigate to different CTU and see the total number of bits used per CTU MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 95 ...

Страница 102: ... Unit Type Partition Type Luma and Chroma Transform Unit Types Slice and Tile partitions Using CU size distribution graph Switching to different decode types such as decode predicted and residual Checking the number of bits per CTU for encoding efficiency Navigating between CTUs 96 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 103: ...llowing Closed caption analysis Using closed caption tooltips Using CC1 services in ATSC608 AFD analysis This tutorial requires that you have completed the previous tutorials and that you can Open example streams Play stop step forward and rewind a video Use and interpret alert pop up messages MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 97 ...

Страница 104: ...file has been opened enable video trace and closed caption analysis a Click Analysis Closed caption enable b In the Closed Caption tab of the Video analysis options window click the Extract CC check box as shown below The rest of the default settings in the Closed Caption tab are OK for this tutorial 98 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 105: ...c In the Video analysis options window click the Trace tab d In the Trace tab scroll down and click User Data as shown below e Click OK to close the Video analysis options window MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials 99 ...

Страница 106: ...ed Show or hide the Closed Caption Availability Panel This closed caption tooltip shows or hides the Closed Caption Availability Panel from the right side of the display When the video is playing the panel shows which closed caption types are available in the stream The available captions are colored green as shown below Show or hide the CEA608 tooltip This closed caption tooltip shows or hides th...

Страница 107: ...sed Caption file When closed caption analysis is enabled and the Extract CC option is enabled this closed caption tooltip displays the extracted closed caption file The caption file displays details about the closed caption contents This tooltip required analysis to be stopped before being active 4 Click the Pause Step button or press Ctrl A to step one frame at a time until you see Display 0006 i...

Страница 108: ...ing into the CC buffers with each frame of new video destined for Row 14 The CEA608 window is showing that the incoming text will have a White foreground and Black background and then Pop On once completed The AFD info has been extracted from the User Data and displayed at the bottom of the CC Availability Panel 102 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 109: ...y button or press Ctrl P to allow the analyzer to play up to Display frame 51 or higher 10 Observe that the closed caption text on rows 14 and 15 have been removed from the display and replaced with Blue text on row 1 11 Click Analysis View Video Trace A new window appears showing each of the selected types of Trace you previously chose User Data as well as the default Stream Summary MTS4EAV7 HEVC...

Страница 110: ... an optional header for each video frame 13 In this case you can find SCTE20 header data followed by ATSC CC User Data header data and finally AFD header data near the end of the list before the next frame 14 Click the Stop button or press Ctrl S to stop the analysis and enable the Extracted CC file icon 104 MTS4EAV7 HEVC AVC Video and Compressed Audio Analyzer Tutorials ...

Страница 111: ...00 48 frames 16 To see the rest of the closed caption text as well as a longer extracted CC file click the Play button to let the file run to the end This will allow you to see many combinations of CC1 to CC4 in both ATSC608 as well as SCTE20 NOTE To view CEA708 closed caption samples you can perform this procedure using the 720p sample stream 720p Tek CC test Conclusion This tutorial demonstrated...

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