[FFmpeg-devel] [PATCH v8 2/3] avcodec/libx264:setting profile and level in avcodec context

[Michael Niedermayer]

On Tue, Dec 19, 2017 at 11:39:24AM +0530, vdixit at akamai.com wrote:
> From: Vishwanath Dixit <vdixit at akamai.com>
> 
> ---
>  libavcodec/libx264.c | 20 +++++++++++++++-----
>  1 file changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/libavcodec/libx264.c b/libavcodec/libx264.c
> index e2455e1..0285213 100644
> --- a/libavcodec/libx264.c
> +++ b/libavcodec/libx264.c
> @@ -19,11 +19,13 @@
>   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
>   */
>  
> +#include "libavutil/avassert.h"
>  #include "libavutil/eval.h"
>  #include "libavutil/internal.h"
>  #include "libavutil/opt.h"
>  #include "libavutil/mem.h"
>  #include "libavutil/pixdesc.h"
> +#include "libavutil/reverse.h"
>  #include "libavutil/stereo3d.h"
>  #include "libavutil/intreadwrite.h"
>  #include "avcodec.h"
> @@ -454,6 +456,9 @@ static av_cold int X264_init(AVCodecContext *avctx)
>      X264Context *x4 = avctx->priv_data;
>      AVCPBProperties *cpb_props;
>      int sw,sh;
> +    x264_nal_t *nal;
> +    uint8_t *p;
> +    int nnal, s, i;
>  
>      if (avctx->global_quality > 0)
>          av_log(avctx, AV_LOG_WARNING, "-qscale is ignored, -crf is recommended.\n");
> @@ -799,12 +804,17 @@ FF_ENABLE_DEPRECATION_WARNINGS
>      if (!x4->enc)
>          return AVERROR_EXTERNAL;
>  
> -    if (avctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER) {
> -        x264_nal_t *nal;
> -        uint8_t *p;
> -        int nnal, s, i;
> +    s = x264_encoder_headers(x4->enc, &nal, &nnal);
> +    // Assert for NAL start code and SPS unit type
> +    av_assert0((nal->p_payload[0] | nal->p_payload[1] | nal->p_payload[2]) == 0 && nal->p_payload[3] == 1);
> +    av_assert0((nal->p_payload[4] & 0x1F) == 7);

> +    // bits 0-7 LSB for profile. bits 8-11 for constrained set flags.
> +    if (avctx->profile == FF_PROFILE_UNKNOWN)
> +        avctx->profile = ((uint32_t)nal->p_payload[5]) | ((uint32_t)ff_reverse[nal->p_payload[6]] << 8);
> +    if (avctx->level == FF_LEVEL_UNKNOWN)
> +        avctx->level = nal->p_payload[7];

As long as the API in avcodec.h specifies these as "encoding: Set by user",
its not allowed to set them from libavcodec.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I do not agree with what you have to say, but I'll defend to the death your
right to say it. -- Voltaire
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