[FFmpeg-devel] [PATCH 2/4] avcodec/encode: restructure the core encoding code

[Anton Khirnov]

Quoting James Almer (2020-02-27 19:02:00)
> This commit follows the same logic as 061a0c14bb, but for the encode API: The
> new public encoding API will no longer be a wrapper around the old deprecated
> one, and the internal API used by the encoders now consists of a single
> receive_packet() callback that pulls frames as required.
> 
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>  libavcodec/avcodec.h  |  12 +-
>  libavcodec/encode.c   | 268 ++++++++++++++++++++++++++++++++----------
>  libavcodec/encode.h   |  39 ++++++
>  libavcodec/internal.h |   7 +-
>  libavcodec/utils.c    |  12 +-
>  5 files changed, 268 insertions(+), 70 deletions(-)
>  create mode 100644 libavcodec/encode.h
> 
> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> +static int encode_simple_internal(AVCodecContext *avctx, AVPacket *avpkt)
> +{
> +    AVCodecInternal   *avci = avctx->internal;
> +    EncodeSimpleContext *es = &avci->es;
> +    AVFrame          *frame = es->in_frame;
> +    AVFrame   *padded_frame = NULL;
> +    int got_packet;
>      int ret;
> -    *got_packet = 0;
>  
> -    av_packet_unref(avctx->internal->buffer_pkt);
> -    avctx->internal->buffer_pkt_valid = 0;
> +    if (!frame->buf[0] && !avci->draining) {
> +        av_frame_unref(frame);
> +        ret = ff_encode_get_frame(avctx, frame);
> +        if (ret < 0 && ret != AVERROR_EOF)
> +            return ret;
> +    }
>  
> -    if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
> -        ret = avcodec_encode_video2(avctx, avctx->internal->buffer_pkt,
> -                                    frame, got_packet);
> -    } else if (avctx->codec_type == AVMEDIA_TYPE_AUDIO) {
> -        ret = avcodec_encode_audio2(avctx, avctx->internal->buffer_pkt,
> -                                    frame, got_packet);
> -    } else {
> -        ret = AVERROR(EINVAL);
> +    if (avci->draining_done)
> +        return AVERROR_EOF;

nit: this check would be better at the top of the function, since it
shouldn't interact with the block above

> +
> +    if (!frame->buf[0]) {
> +        if (!(avctx->codec->capabilities & AV_CODEC_CAP_DELAY ||
> +              avctx->active_thread_type & FF_THREAD_FRAME))
> +            return AVERROR_EOF;
> +
> +        // Flushing is signaled with a NULL frame
> +        frame = NULL;
> +    }
> +
> +    got_packet = 0;
> +
> +    if (avctx->codec->type == AVMEDIA_TYPE_VIDEO) {
> +        if ((avctx->flags & AV_CODEC_FLAG_PASS1) && avctx->stats_out)
> +            avctx->stats_out[0] = '\0';
> +
> +        if (av_image_check_size2(avctx->width, avctx->height, avctx->max_pixels, AV_PIX_FMT_NONE, 0, avctx)) {
> +            ret = AVERROR(EINVAL);
> +            goto end;
> +        }
> +        if (frame) {
> +            if (frame->format == AV_PIX_FMT_NONE)
> +                av_log(avctx, AV_LOG_WARNING, "AVFrame.format is not set\n");
> +            if (frame->width == 0 || frame->height == 0)
> +                av_log(avctx, AV_LOG_WARNING, "AVFrame.width or height is not set\n");
> +        }
> +    } else if (frame && avctx->codec->type == AVMEDIA_TYPE_AUDIO) {
> +        /* extract audio service type metadata */
> +        AVFrameSideData *sd = av_frame_get_side_data(frame, AV_FRAME_DATA_AUDIO_SERVICE_TYPE);
> +        if (sd && sd->size >= sizeof(enum AVAudioServiceType))
> +            avctx->audio_service_type = *(enum AVAudioServiceType*)sd->data;
> +
> +        /* check for valid frame size */
> +        if (avctx->codec->capabilities & AV_CODEC_CAP_SMALL_LAST_FRAME) {
> +            if (frame->nb_samples > avctx->frame_size) {
> +                av_log(avctx, AV_LOG_ERROR, "more samples than frame size (avcodec_encode_audio2)\n");
> +                ret = AVERROR(EINVAL);
> +                goto end;
> +            }
> +        } else if (!(avctx->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE)) {
> +            /* if we already got an undersized frame, that must have been the last */
> +            if (avctx->internal->last_audio_frame) {
> +                av_log(avctx, AV_LOG_ERROR, "frame_size (%d) was not respected for a non-last frame (avcodec_encode_audio2)\n", avctx->frame_size);
> +                ret = AVERROR(EINVAL);
> +                goto end;
> +            }
> +
> +            if (frame->nb_samples < avctx->frame_size) {
> +                ret = pad_last_frame(avctx, &padded_frame, frame);
> +                if (ret < 0)
> +                    goto end;
> +
> +                av_frame_unref(frame);
> +                frame = padded_frame;
> +                avctx->internal->last_audio_frame = 1;
> +            }
> +
> +            if (frame->nb_samples != avctx->frame_size) {
> +                av_log(avctx, AV_LOG_ERROR, "nb_samples (%d) != frame_size (%d) (avcodec_encode_audio2)\n", frame->nb_samples, avctx->frame_size);
> +                ret = AVERROR(EINVAL);
> +                goto end;
> +            }
> +        }
> +    }

Nothing about this block looks specific to the simple encoding API. Some
of those should be in the avcodec_send_frame(), others could possibly be
dropped.


-- 
Anton Khirnov