Android ffmpeg 使用

Outline

1. Video Decode

2. Video Encode

3. Audio Decode

4. Audio Encode

5. libyuv (YUV scaling & Convert ) 比ffmpeg 快

p.s. GoldWave 撥pcm , g711

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• 1. Video Decode

AVCodec *vCodec265 = NULL;
AVCodec *vCodec264 = NULL;

vCodec265 = avcodec_find_decoder(AV_CODEC_ID_HEVC);    //265
vCodec264 = avcodec_find_decoder(AV_CODEC_ID_H264);       //264

AVCodecContext *vCodecCtxarr[32];// 16 for h264 ;  16 for h265

• h265

vCodecCtxarr[nal_ch+16] = avcodec_alloc_context3(vCodec265);

vCodecCtxarr[nal_ch+16]->flags |= AV_CODEC_CAP_DELAY;
vCodecCtxarr[nal_ch+16]->skip_frame = AVDISCARD_BIDIR;
vCodecCtxarr[nal_ch+16]->skip_idct = AVDISCARD_NONREF;
vCodecCtxarr[nal_ch+16]->skip_loop_filter = AVDISCARD_NONREF;
vCodecCtxarr[nal_ch+16]->thread_count = 1;

open codec:

avcodec_open2(vCodecCtxarr[nal_ch+16], vCodec265, NULL)

• h264

vCodecCtxarr[nal_ch] = avcodec_alloc_context3(vCodec264);

vCodecCtxarr[nal_ch]->flags |= AV_CODEC_CAP_DELAY;
vCodecCtxarr[nal_ch]->skip_frame = AVDISCARD_BIDIR;
vCodecCtxarr[nal_ch]->skip_idct = AVDISCARD_NONREF;
vCodecCtxarr[nal_ch]->skip_loop_filter = AVDISCARD_NONREF;
vCodecCtxarr[nal_ch]->thread_count = 1;

open deoce:

avcodec_open2(vCodecCtxarr[nal_ch], vCodec264, NULL)

--------------------decode stream 切換 vCodecCtxarr[ch]  or  vCodecCtxarr[ch+16]----------------

*input data:

AVPacket pkt;
av_init_packet(&pkt);
pkt.data = (unsigned char*) nalData;
pkt.size = nal_length;

*deocode:

AVFrame * pFrame = av_frame_alloc();

int consumed_bytes = avcodec_decode_video2(vCodecCtxarr[nal_ch], pFrame, &got_picture,  &pkt);

轉換format (非必要) , yuv -> RBG565

img_convert_ctx = sws_getContext(
      vCodecCtxarr[nal_ch]->width, vCodecCtxarr[nal_ch]->height,
      vCodecCtxarr[nal_ch]->pix_fmt, vCodecCtxarr[nal_ch]->width,
      vCodecCtxarr[nal_ch]->height,
      AV_PIX_FMT_RGB565, SWS_FAST_BILINEAR, NULL, NULL, NULL);

*close codec

• 2. Video Encode

avcodec_flush_buffers(vCodecCtxarr[nal_ch+16]);

avcodec_free_context(&vCodecCtxarr[nal_ch+16]);
vCodecCtxarr[nal_ch+16] = NULL;

av_free(vCodecCtxarr[nal_ch]);

• 其他如 AVFrame 存為yuv 420:

FILE *pfout = NULL;
void yuv420p_save(AVFrame *pFrame, int mWidth,int mLeight)
{
    int i = 0;

    int width = mWidth, height = mLeight;
    int height_half = height / 2, width_half = width / 2;
    int y_wrap = pFrame->linesize[0];
    int u_wrap = pFrame->linesize[1];
    int v_wrap = pFrame->linesize[2];

    unsigned char *y_buf = pFrame->data[0];
    unsigned char *u_buf = pFrame->data[1];
    unsigned char *v_buf = pFrame->data[2];
    LOGE("qtParserTest....................... real width=%d,height= %d",width,height);
    LOGE("qtParserTest....................... y_wrap= %d,u_wrap= %d,v_wrap= %d",y_wrap,u_wrap,v_wrap);

   //if height=360,width=640,*3/2=> total 345600;y_wrap=640
    //save y
    for (i = 0; i < height; i++)
        fwrite(y_buf + i * y_wrap, 1, width, pfout);//230400 height*width

    //--------------for N12 uv uv;u_wrap=320
//    for (i = 0; i < height_half; i++)
//        fwrite(u_buf + i * u_wrap, 1, width, pfout);//115200 height_half*width

    //-----------------below to for I420
    //save u
    for (i = 0; i < height_half; i++)//57600  height_half*width_half
       fwrite(u_buf + i * u_wrap, 1, width_half, pfout);


    //save v
    for (i = 0; i < height_half; i++)//57600
        fwrite(v_buf + i * v_wrap, 1, width_half, pfout);
    //460800
    fflush(pfout);
}

• 3. Audio Decode  (g726 , aac) g711 用轉表方式

AVCodec        *m_pcodec;
AVCodecContext     *m_pavCtx;
SwrContext    *m_pswrCtx;

• aac:

m_pcodec = avcodec_find_decoder(AV_CODEC_ID_AAC);

m_pavCtx = avcodec_alloc_context3(m_pcodec);

m_pavCtx->channels = 1;
m_pavCtx->sample_rate = i_sample_hz;
m_pavCtx->channel_layout = 1;

avcodec_open2(m_pavCtx, m_pcodec, NULL)

resample:

m_pswrCtx = swr_alloc_set_opts( NULL,
                              m_pavCtx->channel_layout,
                              AV_SAMPLE_FMT_S16,
                              m_pavCtx->sample_rate,
                              m_pavCtx->channels,
                              AV_SAMPLE_FMT_FLTP,
                              m_pavCtx->sample_rate,
                              0,
                              NULL);

output&decode:

AVPacket packet;
av_init_packet(&packet);

packet.size = buffer_size;
packet.data = data;

uint8_t *audio_buf = new uint8_t[10240];
AVFrame *frame = av_frame_alloc();

int len = avcodec_decode_audio4(m_pavCtx, frame, &got_frame, &packet);

int ret = swr_convert(m_pswrCtx, &audio_buf, frame->nb_samples,
                      (const uint8_t **) frame->extended_data, frame->nb_samples);

m_fun_notify(m_penv, (unsigned char *) audio_buf, frame->linesize[0] / 4);

• g726:

m_pcodec = avcodec_find_decoder(AV_CODEC_ID_ADPCM_G726);

m_pavCtx->channels = 1;
m_pavCtx->sample_rate = 8000;
m_pavCtx->bit_rate = (ms32CodeType  * 8);
m_pavCtx->bits_per_coded_sample = ms32CodeType ;

avcodec_open2(m_pavCtx, m_pcodec, NULL)

output &decode :

AVPacket packet;
av_init_packet(&packet);

packet.size = buffer_size;
packet.data = data;

uint8_t *audio_buf = new uint8_t[10240];
AVFrame *frame = av_frame_alloc();

int len = avcodec_decode_audio4(m_pavCtx, frame, &got_frame, &packet);

out:

dst_len=av_samples_get_buffer_size(NULL, m_pavCtx->channels,frame->nb_samples, AV_SAMPLE_FMT_S16, 1);

frame->data[0], dst_len

close:

avcodec_close(m_pavCtx);
av_free(m_pavCtx);
swr_free(&m_pswrCtx);

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