[FFmpeg-devel] [PATCH v2] avformat/mpegts: add option max_packet_size

[Gyan Doshi]

Plan to push tomorrow.

On 2022-01-12 08:57 pm, Gyan Doshi wrote:
> Makes maximum size of emitted packet user-tunable.
> ---
>   doc/demuxers.texi    | 4 ++++
>   libavformat/mpegts.c | 9 ++++++---
>   2 files changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/doc/demuxers.texi b/doc/demuxers.texi
> index 26ae768d7a..aef5976551 100644
> --- a/doc/demuxers.texi
> +++ b/doc/demuxers.texi
> @@ -775,6 +775,10 @@ disabled). Default value is -1.
>   @item merge_pmt_versions
>   Re-use existing streams when a PMT's version is updated and elementary
>   streams move to different PIDs. Default value is 0.
> +
> + at item max_packet_size
> +Set maximum size, in bytes, of packet emitted by the demuxer. Payloads above this size
> +are split across multiple packets. Range is 1 to INT_MAX. Default is 204800 bytes.
>   @end table
>   
>   @section mpjpeg
> diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
> index 2479cb6f7d..6ff1a54706 100644
> --- a/libavformat/mpegts.c
> +++ b/libavformat/mpegts.c
> @@ -162,6 +162,7 @@ struct MpegTSContext {
>   
>       int resync_size;
>       int merge_pmt_versions;
> +    int max_packet_size;
>   
>       /******************************************/
>       /* private mpegts data */
> @@ -198,6 +199,8 @@ static const AVOption options[] = {
>        {.i64 = 0}, 0, 1, 0 },
>       {"skip_clear", "skip clearing programs", offsetof(MpegTSContext, skip_clear), AV_OPT_TYPE_BOOL,
>        {.i64 = 0}, 0, 1, 0 },
> +    {"max_packet_size", "maximum size of emitted packet", offsetof(MpegTSContext, max_packet_size), AV_OPT_TYPE_INT,
> +     {.i64 = MAX_PES_PAYLOAD}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
>       { NULL },
>   };
>   
> @@ -1121,7 +1124,7 @@ static AVBufferRef *buffer_pool_get(MpegTSContext *ts, int size)
>   {
>       int index = av_log2(size + AV_INPUT_BUFFER_PADDING_SIZE);
>       if (!ts->pools[index]) {
> -        int pool_size = FFMIN(MAX_PES_PAYLOAD + AV_INPUT_BUFFER_PADDING_SIZE, 2 << index);
> +        int pool_size = FFMIN(ts->max_packet_size + AV_INPUT_BUFFER_PADDING_SIZE, 2 << index);
>           ts->pools[index] = av_buffer_pool_init(pool_size, NULL);
>           if (!ts->pools[index])
>               return NULL;
> @@ -1368,7 +1371,7 @@ skip:
>               break;
>           case MPEGTS_PAYLOAD:
>               do {
> -                int max_packet_size = MAX_PES_PAYLOAD;
> +                int max_packet_size = ts->max_packet_size;
>                   if (pes->PES_packet_length && pes->PES_packet_length + PES_START_SIZE > pes->pes_header_size)
>                       max_packet_size = pes->PES_packet_length + PES_START_SIZE - pes->pes_header_size;
>   
> @@ -1378,7 +1381,7 @@ skip:
>                       if (ret < 0)
>                           return ret;
>                       pes->PES_packet_length = 0;
> -                    max_packet_size = MAX_PES_PAYLOAD;
> +                    max_packet_size = ts->max_packet_size;
>                       ts->stop_parse = 1;
>                   } else if (pes->data_index == 0 &&
>                              buf_size > max_packet_size) {