Re: [FFmpeg-devel] [PATCH 2/3] ffplay: convert to new decode API

[Marton Balint]

On Fri, 17 Mar 2017, wal...@free.fr wrote:

I tried the patch. Once av_assert0 test is removed, the crystalhd 
decoder is running till send_packet triggers AVERROR(EAGAIN), now the 
crystalhd buffer is likely overflowed, the video freezes. A few seconds 
later the decoder displays a few frames and the cycle goes on.

Im not sure how to properly implement the function to stop or resend 
send_packet frames, this is likely the only mechanism missing.

Hmm. Theoretically an assertion at send_packet can only happen, if the 
CrystalHD decoder is is returning AVERROR(EAGAIN) for receive_frame 
and for send_packet as well, which is forbidden.

Could you add some logging, and log the return values of both send_packet 
and receive_frame to make sure that is the case, and the crystalHD decoder 
is buggy, not my implementation of the new decode API?

I tested h264_cuvid decoder with ffplay (the only decoder with the new 
API), and that worked so I am inclined to think CrystalHD is buggy. And 
the behaviour you described looks like once the buffers of CrystalHD 
is full, but no decoded frame is available yet, it simply returns 
AVERROR(EAGAIN) instead of blocking receive_frame call which it should do.

Thanks,
Marton

Best Regards,
Wallak.



----- Mail original -----
De: "Marton Balint" <c...@passwd.hu>
À: "FFmpeg development discussions and patches" <ffmpeg-devel@ffmpeg.org>
Cc: wal...@free.fr
Envoyé: Jeudi 16 Mars 2017 23:25:18
Objet: Re: [FFmpeg-devel] [PATCH 2/3] ffplay: convert to new decode API



On Wed, 15 Mar 2017, Marton Balint wrote:

Since subtitles are not yet supported with the new API, CODEC_CAP_DELAY
subtitle codecs (only libzvbi so far) may loose the last few buffered frames in
the end of the stream.

The impact of this is so limited, it seemded better to accept it than losing
the simplification benefits of the new API.

Hi Wallak,

Have you had a chance to test this ffplay patch, and see if it fixes 
CrystalHD decoding in ffplay or not?

Thanks,
Marton


Signed-off-by: Marton Balint <c...@passwd.hu>
---
ffplay.c | 92 +++++++++++++++++++++++++++++-----------------------------------
1 file changed, 41 insertions(+), 51 deletions(-)

diff --git a/ffplay.c b/ffplay.c
index cf138dc..06d1d22 100644
--- a/ffplay.c
+++ b/ffplay.c
@@ -186,13 +186,10 @@ enum {
};

typedef struct Decoder {
-    AVPacket pkt;
-    AVPacket pkt_temp;
    PacketQueue *queue;
    AVCodecContext *avctx;
    int pkt_serial;
    int finished;
-    int packet_pending;
    SDL_cond *empty_queue_cond;
    int64_t start_pts;
    AVRational start_pts_tb;
@@ -551,40 +548,24 @@ static void decoder_init(Decoder *d, AVCodecContext 
*avctx, PacketQueue *queue,
    d->queue = queue;
    d->empty_queue_cond = empty_queue_cond;
    d->start_pts = AV_NOPTS_VALUE;
+    d->pkt_serial = -1;
}

static int decoder_decode_frame(Decoder *d, AVFrame *frame, AVSubtitle *sub) {
-    int got_frame = 0;
+    int ret = AVERROR(EAGAIN);

-    do {
-        int ret = -1;
+    for (;;) {
+        AVPacket pkt;

+        if (d->queue->serial == d->pkt_serial) {
+        do {
        if (d->queue->abort_request)
            return -1;

-        if (!d->packet_pending || d->queue->serial != d->pkt_serial) {
-            AVPacket pkt;
-            do {
-                if (d->queue->nb_packets == 0)
-                    SDL_CondSignal(d->empty_queue_cond);
-                if (packet_queue_get(d->queue, &pkt, 1, &d->pkt_serial) < 0)
-                    return -1;
-                if (pkt.data == flush_pkt.data) {
-                    avcodec_flush_buffers(d->avctx);
-                    d->finished = 0;
-                    d->next_pts = d->start_pts;
-                    d->next_pts_tb = d->start_pts_tb;
-                }
-            } while (pkt.data == flush_pkt.data || d->queue->serial != 
d->pkt_serial);
-            av_packet_unref(&d->pkt);
-            d->pkt_temp = d->pkt = pkt;
-            d->packet_pending = 1;
-        }
-
        switch (d->avctx->codec_type) {
            case AVMEDIA_TYPE_VIDEO:
-                ret = avcodec_decode_video2(d->avctx, frame, &got_frame, 
&d->pkt_temp);
-                if (got_frame) {
+                ret = avcodec_receive_frame(d->avctx, frame);
+                if (ret >= 0) {
                    if (decoder_reorder_pts == -1) {
                        frame->pts = av_frame_get_best_effort_timestamp(frame);
                    } else if (!decoder_reorder_pts) {
@@ -593,8 +574,8 @@ static int decoder_decode_frame(Decoder *d, AVFrame *frame, 
AVSubtitle *sub) {
                }
                break;
            case AVMEDIA_TYPE_AUDIO:
-                ret = avcodec_decode_audio4(d->avctx, frame, &got_frame, 
&d->pkt_temp);
-                if (got_frame) {
+                ret = avcodec_receive_frame(d->avctx, frame);
+                if (ret >= 0) {
                    AVRational tb = (AVRational){1, frame->sample_rate};
                    if (frame->pts != AV_NOPTS_VALUE)
                        frame->pts = av_rescale_q(frame->pts, 
av_codec_get_pkt_timebase(d->avctx), tb);
@@ -606,37 +587,46 @@ static int decoder_decode_frame(Decoder *d, AVFrame 
*frame, AVSubtitle *sub) {
                    }
                }
                break;
-            case AVMEDIA_TYPE_SUBTITLE:
-                ret = avcodec_decode_subtitle2(d->avctx, sub, &got_frame, 
&d->pkt_temp);
-                break;
+        }
+        if (ret == AVERROR_EOF) {
+            d->finished = d->pkt_serial;
+            avcodec_flush_buffers(d->avctx);
+            return 0;
+        }
+        if (ret >= 0)
+            return 1;
+        } while (ret != AVERROR(EAGAIN));
        }

-        if (ret < 0) {
-            d->packet_pending = 0;
+        do {
+            if (d->queue->nb_packets == 0)
+                SDL_CondSignal(d->empty_queue_cond);
+            if (packet_queue_get(d->queue, &pkt, 1, &d->pkt_serial) < 0)
+                return -1;
+        } while (d->queue->serial != d->pkt_serial);
+
+        if (pkt.data == flush_pkt.data) {
+            avcodec_flush_buffers(d->avctx);
+            d->finished = 0;
+            d->next_pts = d->start_pts;
+            d->next_pts_tb = d->start_pts_tb;
        } else {
-            d->pkt_temp.dts =
-            d->pkt_temp.pts = AV_NOPTS_VALUE;
-            if (d->pkt_temp.data) {
-                if (d->avctx->codec_type != AVMEDIA_TYPE_AUDIO)
-                    ret = d->pkt_temp.size;
-                d->pkt_temp.data += ret;
-                d->pkt_temp.size -= ret;
-                if (d->pkt_temp.size <= 0)
-                    d->packet_pending = 0;
+            if (d->avctx->codec_type == AVMEDIA_TYPE_SUBTITLE) {
+                int got_frame = 0;
+                ret = avcodec_decode_subtitle2(d->avctx, sub, &got_frame, 
&pkt);
+                if (ret < 0)
+                    ret = AVERROR(EAGAIN);
+                else
+                    ret = got_frame ? 0 : (pkt.data ? AVERROR(EAGAIN) : 
AVERROR_EOF);
            } else {
-                if (!got_frame) {
-                    d->packet_pending = 0;
-                    d->finished = d->pkt_serial;
-                }
+                av_assert0(avcodec_send_packet(d->avctx, &pkt) != 
AVERROR(EAGAIN));
            }
+            av_packet_unref(&pkt);
        }
-    } while (!got_frame && !d->finished);
-
-    return got_frame;
+    }
}

static void decoder_destroy(Decoder *d) {
-    av_packet_unref(&d->pkt);
    avcodec_free_context(&d->avctx);
}

--
2.10.2

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