Generate single MPEGTS HLS segment based on fragmented input data
Hi, the problem I want to describe is similar to "Generate individual HLS-compatible .ts segments on-demand by downloading as little bytes as possible from a remote input file" described here http://ffmpeg.org/pipermail/ffmpeg-user/2016-December/034513.html - unfortunately no answers there. Initial assumptions are: - need to provide streaming solution based on HLS-compatible MPEGTS segments - for now need to stream audio only (maybe audio+video in the future, so generic solution would be the best for me) - my data source is a group of WAV file segments, exactly 10 seconds each - if you take all WAV segments and concatenate them you will get a nice, seamless audio track (no glitches, gaps etc.) - the cost of retrieving each WAV segment from my storage is relatively high My approach: - create m3u8 index file before any segments are actually available, as I know how many segments I need to generate and I also know their duration - when a MPEGTS segment is requested, collect WAV data from storage and generate MPEGTS file using FFmpeg: For first segment: ffmpeg -i input_1.wav -acodec aac -output_ts_offset 0ms output_1.ts For second segment: ffmpeg -i input_2.wav -acodec aac -output_ts_offset 10000ms output_2.ts etc... My problem: - generated segments are not exactly 10 seconds long - gaps can be heard between some audio segments (may this be caused by above issue?) Any ideas how to generate single MPEGTS segments that will not cause glitches during playback? I need to expose the data through web API written in ASP.NET C#. Any idea on how to solve this problem, even if it may not use FFmpeg at all, would be appreciated. Thanks, Jan
On Fri, 11 Dec 2020 18:15:01 +0100 Jan Marlewski <jan.marlewski@gmail.com> wrote:
Hi,
the problem I want to describe is similar to "Generate individual HLS-compatible .ts segments on-demand by downloading as little bytes as possible from a remote input file" described here http://ffmpeg.org/pipermail/ffmpeg-user/2016-December/034513.html - unfortunately no answers there.
Initial assumptions are: - need to provide streaming solution based on HLS-compatible MPEGTS segments - for now need to stream audio only (maybe audio+video in the future, so generic solution would be the best for me) - my data source is a group of WAV file segments, exactly 10 seconds each - if you take all WAV segments and concatenate them you will get a nice, seamless audio track (no glitches, gaps etc.) - the cost of retrieving each WAV segment from my storage is relatively high
My approach: - create m3u8 index file before any segments are actually available, as I know how many segments I need to generate and I also know their duration - when a MPEGTS segment is requested, collect WAV data from storage and generate MPEGTS file using FFmpeg:
For first segment: ffmpeg -i input_1.wav -acodec aac -output_ts_offset 0ms output_1.ts
For second segment: ffmpeg -i input_2.wav -acodec aac -output_ts_offset 10000ms output_2.ts
etc...
My problem: - generated segments are not exactly 10 seconds long - gaps can be heard between some audio segments (may this be caused by above issue?)
I think the problem was caused by separated encoding of independent files, because of the padding and frame size requirement of encoder. My suggestion is process all file at once, these links may help: https://stackoverflow.com/questions/7333232/how-to-concatenate-two-mp4-files... https://trac.ffmpeg.org/wiki/Concatenate
Any ideas how to generate single MPEGTS segments that will not cause glitches during playback?
I need to expose the data through web API written in ASP.NET C#. Any idea on how to solve this problem, even if it may not use FFmpeg at all, would be appreciated.
Thanks, Jan _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user
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-- Best regards, Lingjiang Fang
Thank you for your response Lingjiang Fang. Unfortunately concatenating all files before generating MPEG TS segments would require to download all data from storage, which is not possible in my scenario! When you say "padding and frame size requirement of encoder" do you mean AAC encoder or MPEG TS encoder? Maybe there is a way to fulfill this requirement by using segment length other than 10 seconds? Regards, Jan pon., 14 gru 2020 o 04:56 Lingjiang Fang <vacingfang@foxmail.com> napisał(a):
On Fri, 11 Dec 2020 18:15:01 +0100 Jan Marlewski <jan.marlewski@gmail.com> wrote:
Hi,
the problem I want to describe is similar to "Generate individual HLS-compatible .ts segments on-demand by downloading as little bytes as possible from a remote input file" described here http://ffmpeg.org/pipermail/ffmpeg-user/2016-December/034513.html - unfortunately no answers there.
Initial assumptions are: - need to provide streaming solution based on HLS-compatible MPEGTS segments - for now need to stream audio only (maybe audio+video in the future, so generic solution would be the best for me) - my data source is a group of WAV file segments, exactly 10 seconds each - if you take all WAV segments and concatenate them you will get a nice, seamless audio track (no glitches, gaps etc.) - the cost of retrieving each WAV segment from my storage is relatively high
My approach: - create m3u8 index file before any segments are actually available, as I know how many segments I need to generate and I also know their duration - when a MPEGTS segment is requested, collect WAV data from storage and generate MPEGTS file using FFmpeg:
For first segment: ffmpeg -i input_1.wav -acodec aac -output_ts_offset 0ms output_1.ts
For second segment: ffmpeg -i input_2.wav -acodec aac -output_ts_offset 10000ms output_2.ts
etc...
My problem: - generated segments are not exactly 10 seconds long - gaps can be heard between some audio segments (may this be caused by above issue?)
I think the problem was caused by separated encoding of independent files, because of the padding and frame size requirement of encoder.
My suggestion is process all file at once, these links may help:
https://stackoverflow.com/questions/7333232/how-to-concatenate-two-mp4-files... https://trac.ffmpeg.org/wiki/Concatenate
Any ideas how to generate single MPEGTS segments that will not cause glitches during playback?
I need to expose the data through web API written in ASP.NET C#. Any idea on how to solve this problem, even if it may not use FFmpeg at all, would be appreciated.
Thanks, Jan _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email ffmpeg-user-request@ffmpeg.org with subject "unsubscribe".
-- Best regards, Lingjiang Fang _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email ffmpeg-user-request@ffmpeg.org with subject "unsubscribe".
participants (2)
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Jan Marlewski -
Lingjiang Fang