[Libav-user] Loosing Video Frames

[gaurav mishra]

Yes , the fps and start value doesnt match with the input video. I am
setting up fps of output stream to match inputstream's fps but it has no
effect .
av_stream_set_r_frame_rate(out_stream,av_stream_get_r_
frame_rate(inputStream));

PS - I am now able to recover all the frames. earlier i was not flushing
the encoder for delayed frames. I was flushing only the decoder.

On Tue, Oct 13, 2015 at 5:21 AM, Gonzalo <ggarra13 at gmail.com> wrote:

>
>
> El 12/10/15 a las 10:31, gaurav mishra escribió:
>
> Update -
> I added some code after my main while loop to flush remaining frames from
> codec.
> Also i have added one more variable while configuring my encoder ie
> gop_size. these two changes have improved the situation.
> the lost amount of video has come down to approx 0.9 secs.
>
> *Question- what codec settings i have missed which are required to make
> sure that input and output files are identical.  *
> my current encoder setting code looks like -
>
>             c->codec_id           = inputStream->codec->codec_id;
>             c->bit_rate           = inputStream->codec->bit_rate;
>
>             /* Resolution must be a multiple of two. */
>             c->width              = inputStream->codec->width;
>             c->height             = inputStream->codec->height;
>             c->gop_size           = inputStream->codec->gop_size;
>
>             c->time_base          = inputStream->codec->time_base;
>             out_stream->time_base = inputStream->time_base;
>
> av_stream_set_r_frame_rate(out_stream,av_stream_get_r_frame_rate(inputStream));
>
>             c->pix_fmt            = AV_PIX_FMT_YUV420P;
>             c->sample_aspect_ratio.num =
> inputStream->codec->sample_aspect_ratio.num;
>             c->sample_aspect_ratio.den =
> inputStream->codec->sample_aspect_ratio.den;
>             if (oc->oformat->flags & AVFMT_GLOBALHEADER)
>                   c->flags |= CODEC_FLAG_GLOBAL_HEADER;
>
>
> following are line from ffmpeg -i
> *for input file -*
>
>  Duration: 00:00:30.92, start: 0.040000, bitrate: 998 kb/s
>
>     Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv),
> 1280x720 [SAR 1:1 DAR 16:9], 996 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc
> (default)
>
>     Metadata:
>
>       handler_name    : VideoHandler
>
>
> *for output file - *
>
> Duration: 00:00:30.02, start: 0.000000, bitrate: 1022 kb/s
>
>     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
> 1280x720 [SAR 1:1 DAR 16:9], 1019 kb/s, 25.02 fps, 25 tbr, 25k tbn, 100 tbc
> (default)
>
>     Metadata:
>
>       handler_name    : VideoHandler
>
> Did not check your code, but your output file has a wrong FPS (25.02)
> value and a wrong start value (0.00000).
>
>
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