[FFmpeg-devel] [PATCH] lavc/cbs_av1: restore CodedBitstreamAV1Context when AVERROR(ENOSPC)

James Almer jamrial at gmail.com
Tue Sep 27 06:31:50 EEST 2022


On 9/26/2022 4:23 AM, Xiang, Haihao wrote:
> From: Haihao Xiang <haihao.xiang at intel.com>
> 
> The current pbc might be small for an obu frame, so a new pbc is
> required then parse this obu frame again. Because
> CodedBitstreamAV1Context has already been updated for this obu frame, we
> need to restore CodedBitstreamAV1Context, otherwise
> CodedBitstreamAV1Context doesn't match this obu frame when parsing obu
> frame again, e.g. CodedBitstreamAV1Context.order_hint.
> 
> $ ffmpeg -i input.ivf -c:v copy -f null -
> [...]
> [av1_frame_merge @ 0x558bc3d6f880] ref_order_hint[i] does not match
> inferred value: 20, but should be 22.
> [av1_frame_merge @ 0x558bc3d6f880] Failed to write unit 1 (type 6).
> [av1_frame_merge @ 0x558bc3d6f880] Failed to write packet.
> [obu @ 0x558bc3d6e040] av1_frame_merge filter failed to send output
> packet
> ---
>   libavcodec/cbs_av1.c | 85 ++++++++++++++++++++++++++++++++++----------
>   1 file changed, 67 insertions(+), 18 deletions(-)
> 
> diff --git a/libavcodec/cbs_av1.c b/libavcodec/cbs_av1.c
> index 154d9156cf..585bc72cdb 100644
> --- a/libavcodec/cbs_av1.c
> +++ b/libavcodec/cbs_av1.c
> @@ -1058,15 +1058,33 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>       AV1RawTileData *td;
>       size_t header_size;
>       int err, start_pos, end_pos, data_pos;
> +    CodedBitstreamAV1Context av1ctx;
>   
>       // OBUs in the normal bitstream format must contain a size field
>       // in every OBU (in annex B it is optional, but we don't support
>       // writing that).
>       obu->header.obu_has_size_field = 1;
> +    av1ctx = *priv;
> +
> +    if (priv->sequence_header_ref) {
> +        av1ctx.sequence_header_ref = av_buffer_ref(priv->sequence_header_ref);
> +        if (!av1ctx.sequence_header_ref) {
> +            err = AVERROR(ENOMEM);
> +            goto error;

If this is called, av1ctx.frame_header_ref will be equal to 
priv->frame_header_ref and as such unreferenced twice if not NULL. So 
just return AVERROR(ENOMEM) here.

> +        }
> +    }
> +
> +    if (priv->frame_header_ref) {
> +        av1ctx.frame_header_ref = av_buffer_ref(priv->frame_header_ref);
> +        if (!av1ctx.frame_header_ref) {
> +            err = AVERROR(ENOMEM);
> +            goto error;
> +        }
> +    }
>   
>       err = cbs_av1_write_obu_header(ctx, pbc, &obu->header);
>       if (err < 0)
> -        return err;
> +        goto error;
>   
>       if (obu->header.obu_has_size_field) {
>           pbc_tmp = *pbc;
> @@ -1084,18 +1102,21 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>               err = cbs_av1_write_sequence_header_obu(ctx, pbc,
>                                                       &obu->obu.sequence_header);
>               if (err < 0)
> -                return err;
> +                goto error;
>   
>               av_buffer_unref(&priv->sequence_header_ref);
>               priv->sequence_header = NULL;
>   
>               err = ff_cbs_make_unit_refcounted(ctx, unit);
>               if (err < 0)
> -                return err;
> +                goto error;
>   
>               priv->sequence_header_ref = av_buffer_ref(unit->content_ref);
> -            if (!priv->sequence_header_ref)
> -                return AVERROR(ENOMEM);
> +            if (!priv->sequence_header_ref) {
> +                err = AVERROR(ENOMEM);
> +                goto error;
> +            }
> +
>               priv->sequence_header = &obu->obu.sequence_header;
>           }
>           break;
> @@ -1103,7 +1124,7 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>           {
>               err = cbs_av1_write_temporal_delimiter_obu(ctx, pbc);
>               if (err < 0)
> -                return err;
> +                goto error;
>           }
>           break;
>       case AV1_OBU_FRAME_HEADER:
> @@ -1115,7 +1136,7 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>                                                    AV1_OBU_REDUNDANT_FRAME_HEADER,
>                                                    NULL);
>               if (err < 0)
> -                return err;
> +                goto error;
>           }
>           break;
>       case AV1_OBU_TILE_GROUP:
> @@ -1123,7 +1144,7 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>               err = cbs_av1_write_tile_group_obu(ctx, pbc,
>                                                  &obu->obu.tile_group);
>               if (err < 0)
> -                return err;
> +                goto error;
>   
>               td = &obu->obu.tile_group.tile_data;
>           }
> @@ -1132,7 +1153,7 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>           {
>               err = cbs_av1_write_frame_obu(ctx, pbc, &obu->obu.frame, NULL);
>               if (err < 0)
> -                return err;
> +                goto error;
>   
>               td = &obu->obu.frame.tile_group.tile_data;
>           }
> @@ -1141,7 +1162,7 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>           {
>               err = cbs_av1_write_tile_list_obu(ctx, pbc, &obu->obu.tile_list);
>               if (err < 0)
> -                return err;
> +                goto error;
>   
>               td = &obu->obu.tile_list.tile_data;
>           }
> @@ -1150,18 +1171,19 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>           {
>               err = cbs_av1_write_metadata_obu(ctx, pbc, &obu->obu.metadata);
>               if (err < 0)
> -                return err;
> +                goto error;
>           }
>           break;
>       case AV1_OBU_PADDING:
>           {
>               err = cbs_av1_write_padding_obu(ctx, pbc, &obu->obu.padding);
>               if (err < 0)
> -                return err;
> +                goto error;
>           }
>           break;
>       default:
> -        return AVERROR(ENOSYS);
> +        err = AVERROR(ENOSYS);
> +        goto error;
>       }
>   
>       end_pos = put_bits_count(pbc);
> @@ -1172,7 +1194,7 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>           // Add trailing bits and recalculate.
>           err = cbs_av1_write_trailing_bits(ctx, pbc, 8 - end_pos % 8);
>           if (err < 0)
> -            return err;
> +            goto error;
>           end_pos = put_bits_count(pbc);
>           obu->obu_size = header_size = (end_pos - start_pos + 7) / 8;
>       } else {
> @@ -1190,14 +1212,36 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>       *pbc = pbc_tmp;
>       err = cbs_av1_write_leb128(ctx, pbc, "obu_size", obu->obu_size);
>       if (err < 0)
> -        return err;
> +        goto error;
>   
>       data_pos = put_bits_count(pbc) / 8;
>       flush_put_bits(pbc);
>       av_assert0(data_pos <= start_pos);
>   
> -    if (8 * obu->obu_size > put_bits_left(pbc))
> -        return AVERROR(ENOSPC);
> +    if (8 * obu->obu_size > put_bits_left(pbc)) {
> +        av_buffer_unref(&priv->sequence_header_ref);
> +        av_buffer_unref(&priv->frame_header_ref);
> +        *priv = av1ctx;
> +
> +        if (av1ctx.sequence_header_ref) {
> +            priv->sequence_header_ref = av_buffer_ref(av1ctx.sequence_header_ref);
> +            if (!priv->sequence_header_ref) {
> +                err = AVERROR(ENOMEM);
> +                goto error;
> +            }
> +        }
> +
> +        if (av1ctx.frame_header_ref) {
> +            priv->frame_header_ref = av_buffer_ref(av1ctx.frame_header_ref);
> +            if (!priv->frame_header_ref) {
> +                err = AVERROR(ENOMEM);
> +                goto error;
> +            }
> +        }

Why are you creating new references? They were already copied to priv 
and av1ctx is in the stack, so just return AVERROR(ENOSPC) directly.

> +
> +        err = AVERROR(ENOSPC);
> +        goto error;
> +    }
>   
>       if (obu->obu_size > 0) {
>           memmove(pbc->buf + data_pos,
> @@ -1213,8 +1257,13 @@ static int cbs_av1_write_obu(CodedBitstreamContext *ctx,
>   
>       // OBU data must be byte-aligned.
>       av_assert0(put_bits_count(pbc) % 8 == 0);
> +    err = 0;
>   
> -    return 0;
> +error:
> +    av_buffer_unref(&av1ctx.sequence_header_ref);
> +    av_buffer_unref(&av1ctx.frame_header_ref);
> +
> +    return err;
>   }
>   
>   static int cbs_av1_assemble_fragment(CodedBitstreamContext *ctx,


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