[Libav-user] AV_SEEK_FRAME failing for compressed formats like .wmv .mp4

[ganesh mundhe]

Hello all,

I have been trying to decode videos where I need to offset start position.

I have tried to use AV_seek_frame but it works on raw video format (.y4m)
but fails on mpeg2 compressed formats.

Generally videos are in mp4 or wmv and I need to write for those directly
instead of converting them into .y4m

Here how I’m using it



//When using with time

       double t = 5;//time in seconds

       int64_t timestamp = t * AV_TIME_BASE; //destination time

       AVRational r = av_make_q(1, AV_TIME_BASE);

       if (VideoStreamIndex >= 0) {

              timestamp = av_rescale_q(timestamp, r,

                     fmt_ctx->streams[VideoStreamIndex]->time_base);

       }



       av_seek_frame(fmt_ctx, VideoStreamIndex, timestamp, AVSEEK_FLAG_ANY);

or

if I know the frame no



int frmaeno = 100;

int64_t point = (int64_t(frameno) * pavStream->r_frame_rate.den *
pavStream->time_base.den) / (int64_t(pavStream->r_frame_rate.num)
*pavStream->time_base.num);



av_seek_frame(fmt_ctx, VideoStreamIndex, point, 0);







Tried with avformat_seek_file api too but still failing.

Need help here.





Thanks & Warm Regards,

*Ganesh MUNDHE*
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