ffmpeg获取源的pix-fmt
最近发下，解析不到源文件的pix-fmt，进入如下部分：
if (t >= limit) {
av_log(ic, AV_LOG_VERBOSE, "max_analyze_duration %"PRId64" reached at %"PRId64" microseconds st:%d\n",
limit,
t, pkt->stream_index);
if (ic->flags & AVFMT_FLAG_NOBUFFER)
av_packet_unref(pkt);
break;
}
即verbose下提示:
max_analyze_duration 5000000 reached at 5015510 microseconds st:1
深入代码后，发现是从PPS中得到，最外层的是avformat_find_stream_info，如下：
主要介绍decode_nal_units，get_pixel_format，ff_h264_decode_slice_header。
static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size)
{
...
for (i = 0; i < h->pkt.nb_nals; i++) {
ff_h264_decode_slice_header //进到此函数
{
...
if(!h->context_initialized) {
if ((ret =get_pixel_format(h, 1)) < 0)
return ret;
h->avctx->pix_fmt = ret;
...
}
...
}
}
...
}
h264_slice.c
int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl)
{
...
if ((ret = get_pixel_format(h, 1)) < 0)
return ret;
h->avctx->pix_fmt = ret; //line 1295
...
}
#defineCHROMA(h) ((h)->ps.sps->chroma_format_idc)
#defineCHROMA422(h) ((h)->ps.sps->chroma_format_idc == 2)
#defineCHROMA444(h) ((h)->ps.sps->chroma_format_idc == 3)
static enumAVPixelFormat get_pixel_format(H264Context *h, int force_callback)
{
#defineHWACCEL_MAX (CONFIG_H264_DXVA2_HWACCEL + \
CONFIG_H264_D3D11VA_HWACCEL + \
CONFIG_H264_VAAPI_HWACCEL+ \
(CONFIG_H264_VDA_HWACCEL *2) + \
CONFIG_H264_VIDEOTOOLBOX_HWACCEL + \
CONFIG_H264_VDPAU_HWACCEL)
enum AVPixelFormat pix_fmts[HWACCEL_MAX +2], *fmt = pix_fmts;
const enum AVPixelFormat *choices =pix_fmts;
int i;
switch (h->ps.sps->bit_depth_luma) {
case 9:
if (CHROMA444(h)) {
if (h->avctx->colorspace ==AVCOL_SPC_RGB) {
*fmt++ = AV_PIX_FMT_GBRP9;
} else
*fmt++ = AV_PIX_FMT_YUV444P9;
} else if (CHROMA422(h))
*fmt++ = AV_PIX_FMT_YUV422P9;
else
*fmt++ = AV_PIX_FMT_YUV420P9;
break;
case 10:
if (CHROMA444(h)) {
if (h->avctx->colorspace ==AVCOL_SPC_RGB) {
*fmt++ = AV_PIX_FMT_GBRP10;
} else
*fmt++ = AV_PIX_FMT_YUV444P10;
} else if (CHROMA422(h))
*fmt++ = AV_PIX_FMT_YUV422P10;
else
*fmt++ = AV_PIX_FMT_YUV420P10;
break;
case 12:
if (CHROMA444(h)) {
if (h->avctx->colorspace ==AVCOL_SPC_RGB) {
*fmt++ = AV_PIX_FMT_GBRP12;
} else
*fmt++ = AV_PIX_FMT_YUV444P12;
} else if (CHROMA422(h))
*fmt++ = AV_PIX_FMT_YUV422P12;
else
*fmt++ = AV_PIX_FMT_YUV420P12;
break;
case14:
if (CHROMA444(h)) {
if (h->avctx->colorspace ==AVCOL_SPC_RGB) {
*fmt++ = AV_PIX_FMT_GBRP14;
} else
*fmt++ = AV_PIX_FMT_YUV444P14;
} else if (CHROMA422(h))
*fmt++ = AV_PIX_FMT_YUV422P14;
else
*fmt++ = AV_PIX_FMT_YUV420P14;
break;
case 8:
#ifCONFIG_H264_VDPAU_HWACCEL
*fmt++ = AV_PIX_FMT_VDPAU;
#endif
if (CHROMA444(h)) {
if (h->avctx->colorspace ==AVCOL_SPC_RGB)
*fmt++ = AV_PIX_FMT_GBRP;
else if(h->avctx->color_range == AVCOL_RANGE_JPEG)
*fmt++ = AV_PIX_FMT_YUVJ444P;
else
*fmt++ = AV_PIX_FMT_YUV444P;
} else if (CHROMA422(h)) {
if (h->avctx->color_range ==AVCOL_RANGE_JPEG)
*fmt++ = AV_PIX_FMT_YUVJ422P;
else
*fmt++ = AV_PIX_FMT_YUV422P;
} else {
#ifCONFIG_H264_DXVA2_HWACCEL
*fmt++ = AV_PIX_FMT_DXVA2_VLD;
#endif
#ifCONFIG_H264_D3D11VA_HWACCEL
*fmt++ = AV_PIX_FMT_D3D11VA_VLD;
#endif
#ifCONFIG_H264_VAAPI_HWACCEL
*fmt++ = AV_PIX_FMT_VAAPI;
#endif
#ifCONFIG_H264_VDA_HWACCEL
*fmt++ = AV_PIX_FMT_VDA_VLD;
*fmt++ = AV_PIX_FMT_VDA;
#endif
#ifCONFIG_H264_VIDEOTOOLBOX_HWACCEL
*fmt++ = AV_PIX_FMT_VIDEOTOOLBOX;
#endif
if(h->avctx->codec->pix_fmts)
choices =h->avctx->codec->pix_fmts;
else if (h->avctx->color_range== AVCOL_RANGE_JPEG)
*fmt++ = AV_PIX_FMT_YUVJ420P;
else
*fmt++ = AV_PIX_FMT_YUV420P;
}
break;
default:
av_log(h->avctx, AV_LOG_ERROR,
"Unsupported bit depth%d\n", h->ps.sps->bit_depth_luma);
return AVERROR_INVALIDDATA;
}
*fmt = AV_PIX_FMT_NONE;
for (i=0; choices[i] != AV_PIX_FMT_NONE;i++)
if (choices[i] ==h->avctx->pix_fmt && !force_callback)
return choices[i];
return ff_thread_get_format(h->avctx,choices);
}