[FFmpeg-devel] [PATCH] sbc: do not set sample format in parser

[Marc Gonzalez]

Hello ffmpeg devs,

Any comments on the patch below?

Regards.

On 05/01/2021 16:57, Marc Gonzalez wrote:

> From: Arnaud Vrac <avrac at freebox.fr>
> Date: Tue, 5 Jan 2021 13:47:43 +0100
> 
> Commit bdd31feec934 changed the SBC decoder to only set the output
> sample format on init, instead of setting it explicitly on each frame,
> which is correct. But the SBC parser overrides the sample format to S16,
> which triggers a crash when combining the parser and the decoder.
> 
> Fix the issue by not setting the sample format anymore in the parser,
> which is wrong.
> ---
> We've been seeing the following crash signature:
> 
> Crash reason:  SIGSEGV /0x00000000
> Crash address: 0x0
> 0 	libavcodec.so.58 	sbc_decode_frame
> 1 	libavcodec.so.58 	decode_receive_frame_internal
> 2 	libavcodec.so.58 	avcodec_send_packet
> 3 	fbxbta2dp 		decoder_th_func
> 4 	libpthread.so.0 	start_thread
> 5 	libc.so.6 		thread_start
> 
> NB: call stack obtained via CFI, so not necessarily correct
> ---
>  libavcodec/sbc_parser.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/libavcodec/sbc_parser.c b/libavcodec/sbc_parser.c
> index f56564147a..5549b1951c 100644
> --- a/libavcodec/sbc_parser.c
> +++ b/libavcodec/sbc_parser.c
> @@ -42,7 +42,6 @@ static int sbc_parse_header(AVCodecParserContext *s, AVCodecContext *avctx,
>  
>      if (data[0] == MSBC_SYNCWORD && data[1] == 0 && data[2] == 0) {
>          avctx->channels = 1;
> -        avctx->sample_fmt = AV_SAMPLE_FMT_S16;
>          avctx->sample_rate = 16000;
>          avctx->frame_size = 120;
>          s->duration = avctx->frame_size;
> @@ -66,7 +65,6 @@ static int sbc_parse_header(AVCodecParserContext *s, AVCodecContext *avctx,
>                   + (joint * subbands)) + 7) / 8;
>  
>      avctx->channels = channels;
> -    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
>      avctx->sample_rate = sample_rates[sr];
>      avctx->frame_size = subbands * blocks;
>      s->duration = avctx->frame_size;