[FFmpeg-devel] [PATCH 2/3 v2] avcodec/encode: restructure the old encode API

[Anton Khirnov]

Quoting James Almer (2020-03-26 20:28:12)
> On 3/26/2020 5:57 AM, Anton Khirnov wrote:
> > Quoting James Almer (2020-03-16 22:30:01)
> >> Following the same logic as 061a0c14bb, this commit turns the old encode API
> >> into a wrapper for the new one.
> >>
> >> Signed-off-by: James Almer <jamrial at gmail.com>
> >> ---
> >> This could be squashed with the previous commit, like it was done in 061a0c14bb,
> >> but i figured it would be easier to review this way.
> >>
> >>  libavcodec/encode.c   | 364 +++++++++++++-----------------------------
> >>  libavcodec/internal.h |   1 +
> >>  libavcodec/utils.c    |   8 +
> >>  3 files changed, 116 insertions(+), 257 deletions(-)
> >>
> >> diff --git a/libavcodec/encode.c b/libavcodec/encode.c
> >> index cdea1c6c1e..0fdb9e2df2 100644
> >> --- a/libavcodec/encode.c
> >> +++ b/libavcodec/encode.c
> >> @@ -610,3 +361,102 @@ int attribute_align_arg avcodec_receive_packet(AVCodecContext *avctx, AVPacket *
> >>  
> >>      return 0;
> >>  }
> >> +
> >> +static int compat_encode(AVCodecContext *avctx, AVPacket *avpkt,
> >> +                         int *got_packet, const AVFrame *frame)
> >> +{
> >> +    AVCodecInternal *avci = avctx->internal;
> >> +    AVPacket user_pkt;
> >> +    int ret;
> >> +
> >> +    *got_packet = 0;
> >> +
> >> +    if (frame && avctx->codec->type == AVMEDIA_TYPE_VIDEO) {
> >> +        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");
> >> +    }
> >> +
> >> +    ret = avcodec_send_frame(avctx, frame);
> >> +    if (ret == AVERROR_EOF)
> >> +        ret = 0;
> >> +    else if (ret == AVERROR(EAGAIN)) {
> >> +        /* we fully drain all the output in each encode call, so this should not
> >> +         * ever happen */
> >> +        return AVERROR_BUG;
> >> +    } else if (ret < 0)
> >> +        return ret;
> >> +
> >> +    av_packet_move_ref(&user_pkt, avpkt);
> >> +    while (ret >= 0) {
> >> +        ret = avcodec_receive_packet(avctx, avpkt);
> >> +        if (ret < 0) {
> >> +            if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
> >> +                ret = 0;
> >> +            goto finish;
> >> +        }
> >> +
> >> +        if (avpkt != avci->compat_encode_packet) {
> >> +            if (avpkt->data && user_pkt.data) {
> >> +                if (user_pkt.size >= avpkt->size) {
> >> +                    memcpy(user_pkt.data, avpkt->data, avpkt->size);
> >> +                    av_buffer_unref(&avpkt->buf);
> >> +                    avpkt->buf  = user_pkt.buf;
> >> +                    avpkt->data = user_pkt.data;
> >> +                    av_init_packet(&user_pkt);
> >> +                } else {
> >> +                    av_log(avctx, AV_LOG_ERROR, "Provided packet is too small, needs to be %d\n", avpkt->size);
> >> +                    ret = AVERROR(EINVAL);
> >> +                    goto finish;
> > 
> > Shouldn't the packet be unreffed somewhere in this block?
> 
> Yeah. Fixed locally.
> 
> > 
> >> +                }
> >> +            }
> >> +
> >> +            *got_packet = 1;
> >> +            avpkt = avci->compat_encode_packet;
> >> +        } else {
> >> +            if (!avci->compat_decode_warned) {
> >> +                av_log(avctx, AV_LOG_WARNING, "The deprecated avcodec_encode_* "
> >> +                       "API cannot return all the packets for this encoder. "
> >> +                       "Some packets will be dropped. Update your code to the "
> >> +                       "new encoding API to fix this.\n");
> >> +                avci->compat_decode_warned = 1;
> >> +            }
> > 
> > Same.
> 
> avpkt is avci->compat_encode_packet in this block. It will either be
> unreffed next time avcodec_receive_packet() is called with it, or by
> avcodec_close(). No need to unref it here explicitly, but i can do it if
> you prefer that.

I think it's better not to leave data we're not going to use just lying
around for no reason. So yeah, I'd prefer it to be unreffed here.

-- 
Anton Khirnov