[FFmpeg-devel] start code is not [00 00 00 01] issue

[Hendrik Leppkes]

On Sun, Aug 12, 2018 at 12:42 PM tugouxp <13824125580 at 163.com> wrote:
>
>  hi all:
>     i add log print in function "h264_decode_frame" in order to get the start code infomation of the input packet bitstream,
> and the log is below.  but the result is not expected, for the doucument says each packet should be start with start code "00 00 01" or "00 00 00 01",
>
> if so, why the ffmpeg did not report any error messages to terminal?  is there any mistake of my understanding?
>
> thanks for your kindly support. hi all:
>     i add log print in function "h264_decode_frame" in order to get the start code infomation of the input packet bitstream,
> and the log is below.  but the result is not expected, for the doucument says each packet should be start with start code "00 00 01" or "00 00 00 01",
>
> if so, why the ffmpeg did not report any error messages to terminal?  is there any mistake of my understanding?
>

H264 can exist in two formats, either AnnexB with the start code you
mention, or in MP4 format with a length prefix, but not the start code
you are looking for.
MP4 format is used in MP4/MKV and a variety of other containers, while
AnnexB is often found in raw files and MPEG-TS and its derived
formats.

- Hendrik