[FFmpeg-devel] [PATCH] avcodec: Allow to query number of consumed bytes using the new API

[jannis_wth]

30.01.19 19:51 James Almer:
> On 1/30/2019 3:43 PM, jannis_wth wrote:
>> Okay, so how about this one?
>> This functionality is important if you don't know the packet size you
>> are feeding. It allows you to reconstruct the size.
> 
> In what scenario you can't know the size of the AVPacket you're feeding
> to avcodec_send_packet().
> 
For example when a mp4 container lost its moov atom.

>>
>> 0001-avcodec-Allow-to-query-number-of-consumed-bytes-usin.patch
>>
>> From bad739e4f5e9e78cc6fa799287d758bf27db8208 Mon Sep 17 00:00:00 2001
>> From: user <user at host>
>> Date: Wed, 30 Jan 2019 19:33:08 +0100
>> Subject: [PATCH 1/1] avcodec: Allow to query number of consumed bytes using
>>  the new API
>>
>> Currently the only way to get the number of consumed bytes is by using
>> the deprecated decode_audio4() API. This patch adds a simple function
>> to fix this.
>>
>> Signed-off-by: Jannis Kambs <jannis_wth at gmx.de>
>> ---
>>  libavcodec/avcodec.h | 9 +++++++++
>>  libavcodec/utils.c   | 5 +++++
>>  2 files changed, 14 insertions(+)
>>
>> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
>> index f554c53f0e..43bf84e58b 100644
>> --- a/libavcodec/avcodec.h
>> +++ b/libavcodec/avcodec.h
>> @@ -5714,6 +5714,15 @@ int av_get_audio_frame_duration(AVCodecContext *avctx, int frame_bytes);
>>   */
>>  int av_get_audio_frame_duration2(AVCodecParameters *par, int frame_bytes);
>>  
>> +/**
>> + * This function allows to get the number of remaining bytes after
>> + * avcodec_receive_frame() has been called.
>> + *
>> + * @param avctx the codec context
>> + * @return number of remaining bytes from the input AVPacket.
>> + */
>> +int avcodec_get_remaining_size(AVCodecContext *avctx);
>> +
>>  #if FF_API_OLD_BSF
>>  typedef struct AVBitStreamFilterContext {
>>      void *priv_data;
>> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
>> index d519b16092..638154f974 100644
>> --- a/libavcodec/utils.c
>> +++ b/libavcodec/utils.c
>> @@ -1727,6 +1727,11 @@ int av_get_audio_frame_duration2(AVCodecParameters *par, int frame_bytes)
>>                                      frame_bytes);
>>  }
>>  
>> +int avcodec_get_remaining_size(AVCodecContext *avctx)
>> +{
>> +    return avctx->internal->ds.in_pkt->size;
> 
> This is only used by decoders implementing the AVCodec.decode()
> callback. It will always be zero for any decoder using
> AVCodec.receive_frame(), like Bink Audio, libdav1d, etc.

Well, what would be the correct way then?
Or is there no good way and thus you won't accept such interface?