[FFmpeg-devel] [PATCH] lavc/extract_extradata: Use bytestream api

[Andreas Rheinhardt]

Andriy Gelman:
> From: Andriy Gelman <andriy.gelman at gmail.com>
> 
> Signed-off-by: Andriy Gelman <andriy.gelman at gmail.com>
> ---
>  libavcodec/extract_extradata_bsf.c | 27 +++++++++++++++++----------
>  1 file changed, 17 insertions(+), 10 deletions(-)
> 
> diff --git a/libavcodec/extract_extradata_bsf.c b/libavcodec/extract_extradata_bsf.c
> index ff111de48cb..4a9f6608734 100644
> --- a/libavcodec/extract_extradata_bsf.c
> +++ b/libavcodec/extract_extradata_bsf.c
> @@ -27,6 +27,7 @@
>  #include "av1.h"
>  #include "av1_parse.h"
>  #include "bsf.h"
> +#include "bytestream.h"
>  #include "h2645_parse.h"
>  #include "h264.h"
>  #include "hevc.h"
> @@ -87,6 +88,7 @@ static int extract_extradata_av1(AVBSFContext *ctx, AVPacket *pkt,
>      if (extradata_size && has_seq) {
>          AVBufferRef *filtered_buf;
>          uint8_t *extradata, *filtered_data;
> +        PutByteContext pb_filtered_data, pb_extradata;
>  
>          if (s->remove) {
>              filtered_buf = av_buffer_alloc(filtered_size + AV_INPUT_BUFFER_PADDING_SIZE);
> @@ -108,15 +110,17 @@ static int extract_extradata_av1(AVBSFContext *ctx, AVPacket *pkt,
>          *data = extradata;
>          *size = extradata_size;
>  
> +        bytestream2_init_writer(&pb_extradata, extradata, extradata_size);
> +        if (s->remove)
> +            bytestream2_init_writer(&pb_filtered_data, filtered_data, filtered_size);
> +
>          for (i = 0; i < s->av1_pkt.nb_obus; i++) {
>              AV1OBU *obu = &s->av1_pkt.obus[i];
>              if (val_in_array(extradata_obu_types, nb_extradata_obu_types,
>                               obu->type)) {
> -                memcpy(extradata, obu->raw_data, obu->raw_size);
> -                extradata += obu->raw_size;
> +                bytestream2_put_buffer(&pb_extradata, obu->raw_data, obu->raw_size);
>              } else if (s->remove) {
> -                memcpy(filtered_data, obu->raw_data, obu->raw_size);
> -                filtered_data += obu->raw_size;
> +                bytestream2_put_buffer(&pb_filtered_data, obu->raw_data, obu->raw_size);
>              }
>          }
>  
> @@ -181,6 +185,7 @@ static int extract_extradata_h2645(AVBSFContext *ctx, AVPacket *pkt,
>           (ctx->par_in->codec_id == AV_CODEC_ID_H264 && has_sps))) {
>          AVBufferRef *filtered_buf;
>          uint8_t *extradata, *filtered_data;
> +        PutByteContext pb_filtered_data, pb_extradata;
>  
>          if (s->remove) {
>              filtered_buf = av_buffer_alloc(filtered_size + AV_INPUT_BUFFER_PADDING_SIZE);
> @@ -202,17 +207,19 @@ static int extract_extradata_h2645(AVBSFContext *ctx, AVPacket *pkt,
>          *data = extradata;
>          *size = extradata_size;
>  
> +        bytestream2_init_writer(&pb_extradata, extradata, extradata_size);
> +        if (s->remove)
> +            bytestream2_init_writer(&pb_filtered_data, filtered_data, filtered_size);
> +
>          for (i = 0; i < s->h2645_pkt.nb_nals; i++) {
>              H2645NAL *nal = &s->h2645_pkt.nals[i];
>              if (val_in_array(extradata_nal_types, nb_extradata_nal_types,
>                               nal->type)) {
> -                AV_WB24(extradata, 1); // startcode
> -                memcpy(extradata + 3, nal->raw_data, nal->raw_size);
> -                extradata += 3 + nal->raw_size;
> +                bytestream2_put_be24(&pb_extradata, 1); //startcode
> +                bytestream2_put_buffer(&pb_extradata, nal->raw_data, nal->raw_size);
>              } else if (s->remove) {
> -                AV_WB24(filtered_data, 1); // startcode
> -                memcpy(filtered_data + 3, nal->raw_data, nal->raw_size);
> -                filtered_data += 3 + nal->raw_size;
> +                bytestream2_put_be24(&pb_filtered_data, 1); // startcode
> +                bytestream2_put_buffer(&pb_filtered_data, nal->raw_data, nal->raw_size);
>              }
>          }
>  
This API has both safe (i.e. it checks whether the output buffer's
size is big enough) as well as unsafe (i.e. it just copies as now)
versions (the unsafe ones end with 'u'). Your patch would add checks,
although the size has already been exactly calculated.

- Andreas