Hello,
For experiment, i am reading a flv file, reading its packet and outputing it in
a new flv file. Basically copying a file but in a different manner. For video
stream, I read a full frame, decode it using avcodec_video_decoder. Then I again
encode it using avcodec_video_encode and then I try to write the packet. For the
first frame, it works fine, but for the rest of the frame, it throws me the
following error:
[flv @ 0x9932e50]Error, Invalid timestamp=0, last=0
On debugging further, I see that except for the first frame, when I decode the
frame, I get a response of -1.
while(av_read_frame(pFormatCtx, &packet)>=0) {
if(packet.stream_index==audioStream) {
frameFinished = AVCODEC_MAX_AUDIO_FRAME_SIZE;
avcodec_decode_audio2(pCodecCtx, samples, &frameFinished,
packet.data, packet.size);
// Did we get a video frame?
if(frameFinished) {
AVPacket pkt;
av_init_packet(&pkt);
pkt.size= avcodec_encode_audio(audio_st->codec, audio_outbuf,
audio_outbuf_size, samples);
if (audio_st->codec->coded_frame->pts != AV_NOPTS_VALUE)
pkt.pts= av_rescale_q(audio_st->codec->coded_frame->pts,
audio_st->codec->time_base, audio_st->time_base);
pkt.flags |= PKT_FLAG_KEY;
pkt.stream_index= audio_st->index;
pkt.data= audio_outbuf;
if (av_write_frame(oc, &pkt) != 0) {
fprintf(stderr, "Error while writing audio frame\n");
exit(1);
}
}
}
// Is this a packet from the video stream?
if(packet.stream_index==videoStream) {
// Decode video frame
avcodec_decode_video(pCodecCtx, pFrame, &frameFinished,
packet.data, packet.size);
// Did we get a video frame?
if(frameFinished) {
int w = pCodecCtx->width;
int h = pCodecCtx->height;
int numBytes=avpicture_get_size(video_st->codec->pix_fmt, w,h);
uint8_t *buf=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
int out_size = avcodec_encode_video(video_st->codec, buf,
numBytes,pFrame);
if (out_size > 0) {
AVPacket pkt;
av_init_packet(&pkt);
if (video_st->codec->coded_frame->pts != AV_NOPTS_VALUE)
pkt.pts= av_rescale_q(video_st->codec->coded_frame->pts,
video_st->codec->time_base, video_st->time_base);
if(video_st->codec->coded_frame->key_frame)
pkt.flags |= PKT_FLAG_KEY;
pkt.stream_index= video_st->index;
pkt.data= buf;
pkt.size= numBytes;
// Write it to the output file
if (av_write_frame(oc, &pkt) != 0) {
fprintf(stderr, "Error while writing vedio frame\n");
exit(1);
}
}
}
}
// Free the packet that was allocated by av_read_frame
av_free_packet(&packet);
}
I dont know whats going wrong.
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