[Libav-user] Decoding Problem (got_picture always return 0)

[Việt Hùng Nguyễn]

Hi, you should use CODEC_ID_H264, cause libx264 produces h.264 video stream
and ffmpeg mpeg4 decoder can not decode h.264 video stream.

Hung, Nguyen Viet
On Mar 23, 2012 8:11 PM, "ZHAO Yinxia" <hydezhao at gmail.com> wrote:

> Hi huanggh0108,
>
> I am sure I have no audio frame... While, I use libx264 to encode the
> frames, and I am not sure I chose the right CODEC_ID for decoding.
>
> I use CODEC_ID_MPEG4. CODEC_ID_H264 looks more reasonable, but returns a
> "no frame" error.
>
> 2012/3/23 huanggh0108 <huanggh0108 at sina.com>
>
>> **
>> I guess the data may be audio frame, not video frame.  The data should be
>> filtered before sending at the server end.
>>
>>
>> 2012-03-23
>> ------------------------------
>>  huanggh0108
>> ------------------------------
>> *发件人：* Yinxia
>> *发送时间：* 2012-03-23  00:52:01
>> *收件人：* libav-user
>> *抄送：*
>> *主题：* [Libav-user] Decoding Problem (got_picture always return 0)
>>   Hi dear all,
>>
>> I am a newbie to ffmpeg and I would like to decode the bitstream, which is
>> encoded using libx264 at the server end and sent to client frame by frame.
>>  I wrote a function decodeFrame to decode this bitstream frame by frame,
>> this function is called in a loop, each time recieves a new frame:
>>  void decodeFrame( int size, unsigned char *data)
>> {
>>  avpkt.size = size;
>> avpkt.data = (uint8_t *)(data);
>>  /*decode each frame*/
>>  len = avcodec_decode_video2(c, picture, &got_picture, avpkt.size);
>> if (len < 0) {
>>  fprintf(stderr, "[avcodec][Err] Error while decoding frame %d\n",frame);
>>  exit(1);
>> }
>>  if (got_picture) {
>> printf("[avcodec] Saving frame %3d\n",frame);
>>  fflush(stdout);
>> _snprintf(buf, sizeof(buf), "/temp/video%d.pgm", frame); // not found
>>
>>  pgmSave(picture->data[0], picture->linesize[0], c->width, c->height, buf);
>>  frame++;
>> }
>> }
>>  I can successfully get the value of len, which is exactly the size of
>> frame, however, *the value of *got_picture *is always 0. *Can anyone help
>> me with this?
>> *
>> *
>> PS. this is the init function of decoder.
>>  void initDecoder()
>> {
>> avcodec_register_all();
>>  av_init_packet(&avpkt);
>> memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE);
>>  printf("[avcodec] Frame decoding initializing\n");
>>  /*choose correct video decoder*/
>>  codec = avcodec_find_decoder(CODEC_ID_MPEG4);
>> if ( !codec ) {
>> fprintf(stderr, "[avcodec][Err] codec not found!\n");
>>  exit(1);
>> }
>>  c = avcodec_alloc_context3(codec);
>>  picture = avcodec_alloc_frame();
>>  if(codec->capabilities&CODEC_CAP_TRUNCATED)
>>            c->flags|= CODEC_FLAG_TRUNCATED; /* we do not send complete
>> frames */
>>      /* open it */
>>     if (avcodec_open2(c, codec, NULL) < 0) {
>>         fprintf(stderr, "[avcodec][Err] could not open codec\n");
>>         exit(1);
>>     }
>>  frame = 0;
>>  }
>>  Thank you very much!
>> Yinxia
>>  --
>> View this message in context:
>> http://libav-users.943685.n4.nabble.com/Decoding-Problem-got-picture-always-return-0-tp4496039p4496039.html
>> Sent from the libav-users mailing list archive at Nabble.com.
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>>
>
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