[Libav-user] Reuse of format context after free and reallocate?

[Paul B Mahol]

On Wed, Mar 3, 2021 at 5:50 PM william keeling <williamkeeling at hotmail.com>
wrote:

> I have not used "valgrind" I will need to look into that tool.  any tips
> on how to use it?
>
>
If you are on Linux, using it is very easy.



> yes, I am free the all contexts before reallocation but I cannot find a
> way to for the FLVContext/Muxer to be freed/reinitialized thru the API.
> I am doing the following:
>
> avcodec_free_context() of all streams video and audio
>
> avformat_free_context()
>
> avio_close()
>

If you really do all this than that error would never happen.


>
> ------------------------------
> *From:* Libav-user <libav-user-bounces at ffmpeg.org> on behalf of Paul B
> Mahol <onemda at gmail.com>
> *Sent:* Wednesday, March 3, 2021 5:54 AM
> *To:* This list is about using libavcodec, libavformat, libavutil,
> libavdevice and libavfilter. <libav-user at ffmpeg.org>
> *Subject:* Re: [Libav-user] Reuse of format context after free and
> reallocate?
>
>
>
> On Wed, Mar 3, 2021 at 5:22 AM william keeling <williamkeeling at hotmail.com>
> wrote:
>
>  I did some digging and found the error is coming from this code in
> flvenv.c line 921.
>
>   if (pkt->dts < -flv->delay) {
>         av_log(s, AV_LOG_WARNING,
>                "Packets are not in the proper order with respect to
> DTS\n");
>         return AVERROR(EINVAL);
>
> flv is a pointer to  FLVContext from AVFormatContext->priv_data.
>
> Looks like the avformat_write_header()/avformat_init_output uses the state
> of the muxer at the last run even if the AVFormatContext has been freed and
> reallocated.
> So how do I get the FLVContext to be initlized as if a fresh run. Or how
> do I free the old FLVContext so when avformat_write_header() initlizes the
> priv_data it is fresh.
> ------------------------------
> *From:* Libav-user <libav-user-bounces at ffmpeg.org> on behalf of william
> keeling <WilliamKeeling at hotmail.com>
> *Sent:* Monday, March 1, 2021 2:32 PM
> *To:* libav-user at ffmpeg.org <libav-user at ffmpeg.org>
> *Subject:* [Libav-user] Reuse of format context after free and reallocate?
>
>
> I have a program the creates flash format stream and is work the first
> time thru but when I process the second stream, I get DTS/PTS non
> monotonically errors.
>
> After each stream I free and reallocate all contexts:
>
> avcodec_free_context() of all streams video and audio
>
> avformat_free_context()
>
> avio_close()
>
>
>
> What am I missing so the format context can be reallocate and used?
>
>
> Looks like to be real bug to me.
>
>
>
>
> Thanks William
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