[Libav-user] Decoding opus

He Lei helei0908 at hotmail.com
Wed Jan 11 15:23:10 EET 2017

do you say ,you write same packet to decoder, and get frame more then in packet?
look at anntation as avcodec_decode_audio4???
that is?

4643  * Some decoders may support multiple frames in a single AVPacket. Such

4644  * decoders would then just decode the first frame and the return value would be

4645  * less than the packet size. In this case, avcodec_decode_audio4 has to be

4646  * called again with an AVPacket containing the remaining data in order to

4647  * decode the second frame, etc...  Even if no frames are returned, the packet

4648  * needs to be fed to the decoder with remaining data until it is completely

4649  * consumed or an error occurs.

4650  *

good luck
???? iPhone

? 2017?1?11??20:08?Aboobeker Sidhik Koyamparambil mammu <aboosidhik at gmail.com<mailto:aboosidhik at gmail.com>> ???

Dear All,

I am trying to decode opus. When I use both methods
avcodec_decode_audio4 and (avcodec_send_packet /avcodec_receive_frame) . I am receiving the same opus packet that I send for decoding. I got this by using the packet size of the decoded frame. Packet size is same as the input opus packet size.

I followed the decoding example given in github of ffmpeg. Please help me. Why I am receiving same packet as input?

AVCodec *codec;
AVCodecContext *c = NULL;
AVPacket avpkt;
AVFrame *decoded_frame = NULL;
codec = avcodec_find_decoder(AV_CODEC_ID_OPUS);
if (!codec) {
     printf("Codec not found\n");
c = avcodec_alloc_context3(codec);
if (!c) {
   printf("Could not allocate audio codec context\n");
/* put sample parameters */
c->sample_rate = 48000;
c->request_sample_fmt = AV_SAMPLE_FMT_FLT;
c->channels = 2;
/* open it */
if (avcodec_open2(c, codec, NULL) < 0) {
    printf("Could not open codec\n");

AVPacket avpkt;
AVFrame *decoded_frame = NULL;
avpkt.data = Buffer;  // Buffer is packet data here
avpkt.size = len;    // length of the packet
int i, ch;

if (!decoded_frame) {
    if (!(decoded_frame = av_frame_alloc())) {
        RELAY_SERVER_PRINT("Could not allocate audio frame\n");
int ret;
int got_frame = 0;
ret = avcodec_decode_audio4(client_sockt_num_1->c, decoded_frame, &got_frame, &avpkt);
if (ret < 0) {
        fprintf(stderr, "Error decoding audio frame (%s)\n", av_err2str(ret));
        return ret;
printf("length %i\n", decoded_frame->pkt_size);

Kind Regards

Aboobeker Sidhik
Libav-user mailing list
Libav-user at ffmpeg.org<mailto:Libav-user at ffmpeg.org>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ffmpeg.org/pipermail/libav-user/attachments/20170111/66c95f59/attachment.html>

More information about the Libav-user mailing list