[Libav-user] Encoding to MPEG2 buffer sizing

[Jonathan Noble]

I have had a playaround with ffmpeg to get an understanding of what
rc_buffer_size needs to be set to but that didn't provide much information.
Instead I stepped through ffmpeg and I can see that there are 2 buffers
that need to be set up. 1 is in AVCodecContext, the other is in AVStream,

Setting AVCodecContext->rc_buffer_size seems to have to be done in units of
KB. If i use bits as the unit I see this

> [mpeg2video @ 0x7f3a2c805600] Warning vbv_delay will be set to 0xFFFF
(=VBR) as the specified vbv buffer is too large for the given bitrate!


As for setting the buffer in AVStream, I cannot see how it is done.
mpegenc.c gets the buffer_size in a struct AVCPBProperties using a call to
av_stream_get_side_data.

How does one set the values in AVCPBProperties in the AVStream?


On Wed, 25 Sep 2019 at 22:20, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:

> Am Mi., 25. Sept. 2019 um 22:57 Uhr schrieb Jonathan Noble
> <jonnobleuk at gmail.com>:
>
> > [mpeg @ 0x7f33b8004200] ac3 in MPEG-1 system streams is not widely
> supported,
> > consider using the vob or the dvd muxer to force a MPEG-2 program stream.
>
> Note that independently of your question (I suggest to test with the
> cli), the output
> file will be unplayable with most players as ac3 in mpeg-1 system streams
> are
> typically unsupported (as written above).
>
> Carl Eugen
> _______________________________________________
> Libav-user mailing list
> Libav-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/libav-user
>
> To unsubscribe, visit link above, or email
> libav-user-request at ffmpeg.org with subject "unsubscribe".
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ffmpeg.org/pipermail/libav-user/attachments/20191004/4529860b/attachment.html>