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  1. Looking for an audio bitrate viewer for AAC VBR.

    A graph of time vs bit-rate would be really great...
    Like in the bitrate viewer for video...

    Or any other way to check the bitrate variations and distribution of VBR AAC audio...
    Thanks
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  2. Member
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    Aug 2010
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    It's a bit roundabout, but you could extract audio frame data to a CSV file with FFmpeg:
    ffprobe -select_streams a -show_frames -i input_file -of csv > output_file.csv
    Then import to Excel, add a column to do the bitrate calculation for each row based on pkt_size (in bytes) divided by pkt_duration, and graph pkt_pts_time against the result.
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  3. Member Cornucopia's Avatar
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    What context is there a need for this? (Normally, the proportion of audio bitrate to video bitrate is so miniscule as it wouldn't matter too much in terms of budget, and all you would need would be the average, or the max).

    Scott
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  4. Thanks

    @Cornucopia
    Not for a specific reason that related to practical use...
    Max and Average values can be would be enough for those cases and Mediainfo would show them...
    What I need is to see how they distributed, and for a specific single value, the Minimum bitrate would be then...
    But what i want is not a specific value but the general graph...


    @JVRaines
    I did run the code you given...
    I got the CSV, all good...
    But id does not contain a header row that typically describes what fields are....
    Just the values... No idea abt what are pkt_ fields...
    Any idea or any place that I can find it.. ( I searched a bit and found certain examples, but those have more fields than the result I got)
    Just posting first 3 rows I got for my test M4A file...

    frame,audio,1,2112,0.044,2112,0.044,2048,0.042667, 960,0.02,248700,10,fltp,960,2,stereo
    frame,audio,1,3072,0.064,3072,0.064,3072,0.064,102 4,0.021333,248710,10,fltp,1024,2,stereo
    frame,audio,1,4096,0.085333,4096,0.085333,4096,0.0 85333,1024,0.021333,248720,10,fltp,1024,2,stereo

    !?
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  5. Member
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    Here's a header row.

    frame,media_type,key_frame,pkt_pts,pkt_pts_time,pk t_dts,pkt_dts_time,best_effort_timestamp,best_effo rt_timestamp_time,pkt_duration,pkt_duration_time,p kt_pos,pkt-size,sample_fmt,nb_samples,channels,channel_layout
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  6. A bit late but perhaps useful for somebody:

    Code:
    @ffprobe -select_streams a -i %1 -show_entries "frame=pkt_dts,pkt_dts_time,pkt_pts_time,pkt_duration_time,pkt_pos,pkt_size,best_effort_timestamp,best_effort_timestamp_time,sample_fmt,nb_samples,channels,channel_layout" -pretty -print_format json -of json > %1.json
    
    @ffprobe -select_streams a -i %1 -show_entries "frame=pkt_dts,pkt_dts_time,pkt_pts_time,pkt_duration_time,pkt_pos,pkt_size,best_effort_timestamp,best_effort_timestamp_time,sample_fmt,nb_samples,channels,channel_layout" -pretty -print_format csv -of csv > %1.csv
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  7. Thanks Everybody!
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