[FFmpeg-devel] [PATCH] avformat/pcmdec: add support to set channel layout
James Almer
jamrial at gmail.com
Fri Mar 18 20:32:02 EET 2022
On 3/18/2022 3:24 PM, Paul B Mahol wrote:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
> libavformat/pcmdec.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/libavformat/pcmdec.c b/libavformat/pcmdec.c
> index c7da740541..775cda8cc7 100644
> --- a/libavformat/pcmdec.c
> +++ b/libavformat/pcmdec.c
> @@ -22,6 +22,7 @@
> #include "config_components.h"
>
> #include "libavutil/avstring.h"
> +#include "libavutil/channel_layout.h"
> #include "avformat.h"
> #include "internal.h"
> #include "pcm.h"
> @@ -33,6 +34,7 @@ typedef struct PCMAudioDemuxerContext {
> AVClass *class;
> int sample_rate;
> int channels;
> + char *ch_layout_str;
> } PCMAudioDemuxerContext;
>
> static int pcm_read_header(AVFormatContext *s)
> @@ -41,6 +43,7 @@ static int pcm_read_header(AVFormatContext *s)
> AVCodecParameters *par;
> AVStream *st;
> uint8_t *mime_type = NULL;
> + int ret;
>
> st = avformat_new_stream(s, NULL);
> if (!st)
> @@ -50,7 +53,14 @@ static int pcm_read_header(AVFormatContext *s)
> par->codec_type = AVMEDIA_TYPE_AUDIO;
> par->codec_id = s->iformat->raw_codec_id;
> par->sample_rate = s1->sample_rate;
> - par->ch_layout.nb_channels = s1->channels;
> + if (s1->ch_layout_str) {
> + ret = av_channel_layout_from_string(&par->ch_layout,
> + s1->ch_layout_str);
> + if (ret < 0)
> + return ret;
> + } else {
> + par->ch_layout.nb_channels = s1->channels;
> + }
>
> av_opt_get(s->pb, "mime_type", AV_OPT_SEARCH_CHILDREN, &mime_type);
> if (mime_type && s->iformat->mime_type) {
> @@ -99,6 +109,7 @@ static int pcm_read_header(AVFormatContext *s)
> static const AVOption pcm_options[] = {
> { "sample_rate", "", offsetof(PCMAudioDemuxerContext, sample_rate), AV_OPT_TYPE_INT, {.i64 = 44100}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
> { "channels", "", offsetof(PCMAudioDemuxerContext, channels), AV_OPT_TYPE_INT, {.i64 = 1}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
This option should be deprecated here and in every other raw demuxer in
favor of a new ch_layout one like the one you're introducing, and the
code in ffmpeg.c looking for them adapted.
> + { "ch_layout", "", offsetof(PCMAudioDemuxerContext, ch_layout_str),AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_DECODING_PARAM },
AV_OPT_TYPE_CHLAYOUT. That way you don't need to bother with
av_channel_layout_from_string(), and use av_channel_layout_copy() instead.
> { NULL },
> };
> static const AVClass pcm_demuxer_class = {
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