James Almer:
> On 4/10/2021 9:39 PM, Andreas Rheinhardt wrote:
>> They are essentially forbidden in our encoding API as they are
>> considered empty. So just set the data, but leave the size at zero.
>
> This doesn't seem like a good solution. You're propagating dummy packets
> when the encoder didn't produce any. It's an ugly hack to workaround a
> misbehaving muxer.
> As this is a AV_CODEC_CAP_DELAY encoder, you're supposed to set
> got_packet to 0 in this scenario.
>
> The muxer should then not expect this encoder to return more than one
> packet, which is all it ever truly produces, to assume it effectively
> came from it.
>
Then feel free to fix this yourself. All I know is that the muxer
explicitly checks for the number of frames to be > 1. Not that I know
why. (And I also presume the "Note: without the following, avio only
writes 8 bytes to the file" to be outdated.)
>>
>> (The old encoding API allowed such packets: It used buffer_pkt_valid
>> to record whether the packet is empty or not. This has been changed
>> in 827d6fe73d2f5472c1c2128eb14fab6a4db29032 which broke said encoder.
>> Said regression has been reported in #9179 which this commit partially
>> fixes.)
>>
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com>
>> ---
>> libavcodec/libwebpenc_animencoder.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/libavcodec/libwebpenc_animencoder.c
>> b/libavcodec/libwebpenc_animencoder.c
>> index 7f35a0b939..d871e85d43 100644
>> --- a/libavcodec/libwebpenc_animencoder.c
>> +++ b/libavcodec/libwebpenc_animencoder.c
>> @@ -34,6 +34,7 @@ typedef struct LibWebPAnimContext {
>> WebPAnimEncoder *enc; // the main AnimEncoder object
>> int64_t prev_frame_pts; // pts of the previously encoded frame.
>> int done; // If true, we have assembled the
>> bitstream already
>> + uint8_t padding_buf[AV_INPUT_BUFFER_PADDING_SIZE];
>> } LibWebPAnimContext;
>> static av_cold int libwebp_anim_encode_init(AVCodecContext *avctx)
>> @@ -103,6 +104,8 @@ static int
>> libwebp_anim_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
>> }
>> pkt->pts = pkt->dts = frame->pts;
>> + // Packets without data and side-data are not supported by
>> the API
>> + pkt->data = s->padding_buf;
>> s->prev_frame_pts = frame->pts; // Save for next frame.
>> ret = 0;
>> *got_packet = 1;
>>
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
