Re: [FFmpeg-devel] [PATCH 1/2] tests: Add stream dump test API util, use it to dump stream data for chained ogg/{vorbis, opus, flac} streams.

[Lynne <dev@lynne.ee>]

On 26/04/2025 05:11, Michael Niedermayer wrote:
> On Tue, Apr 22, 2025 at 04:44:07PM -0500, Romain Beauxis wrote:
>> ---
>>   tests/Makefile                             |   4 +
>>   tests/api/Makefile                         |   2 +-
>>   tests/api/api-dump-stream-meta-test.c      | 177 +++++++++++++++++++++
>>   tests/fate/ogg-flac.mak                    |  11 ++
>>   tests/fate/ogg-opus.mak                    |  11 ++
>>   tests/fate/ogg-vorbis.mak                  |  11 ++
>>   tests/ref/fate/ogg-flac-chained-meta.txt   |  12 ++
>>   tests/ref/fate/ogg-opus-chained-meta.txt   |  27 ++++
>>   tests/ref/fate/ogg-vorbis-chained-meta.txt |  17 ++
>>   9 files changed, 271 insertions(+), 1 deletion(-)
>>   create mode 100644 tests/api/api-dump-stream-meta-test.c
>>   create mode 100644 tests/fate/ogg-flac.mak
>>   create mode 100644 tests/fate/ogg-opus.mak
>>   create mode 100644 tests/fate/ogg-vorbis.mak
>>   create mode 100644 tests/ref/fate/ogg-flac-chained-meta.txt
>>   create mode 100644 tests/ref/fate/ogg-opus-chained-meta.txt
>>   create mode 100644 tests/ref/fate/ogg-vorbis-chained-meta.txt
>>
>> diff --git a/tests/Makefile b/tests/Makefile
>> index f9f5fc07f3..75b9bcc729 100644
>> --- a/tests/Makefile
>> +++ b/tests/Makefile
>> @@ -219,6 +219,9 @@ include $(SRC_PATH)/tests/fate/mpeg4.mak
>>   include $(SRC_PATH)/tests/fate/mpegps.mak
>>   include $(SRC_PATH)/tests/fate/mpegts.mak
>>   include $(SRC_PATH)/tests/fate/mxf.mak
>> +include $(SRC_PATH)/tests/fate/ogg-vorbis.mak
>> +include $(SRC_PATH)/tests/fate/ogg-flac.mak
>> +include $(SRC_PATH)/tests/fate/ogg-opus.mak
>>   include $(SRC_PATH)/tests/fate/oma.mak
>>   include $(SRC_PATH)/tests/fate/opus.mak
>>   include $(SRC_PATH)/tests/fate/pcm.mak
>> @@ -277,6 +280,7 @@ $(FATE_FFPROBE) $(FATE_FFMPEG_FFPROBE) $(FATE_SAMPLES_FFPROBE) $(FATE_SAMPLES_FF
>>   $(FATE_SAMPLES_FASTSTART): tools/qt-faststart$(EXESUF)
>>   $(FATE_SAMPLES_DUMP_DATA) $(FATE_SAMPLES_DUMP_DATA-yes): tools/venc_data_dump$(EXESUF)
>>   $(FATE_SAMPLES_SCALE_SLICE): tools/scale_slice_test$(EXESUF)
>> +$(FATE_SAMPLES_DUMP_STREAM_META): tests/api/api-dump-stream-meta-test$(EXESUF)
>>   
>>   ifdef SAMPLES
>>   FATE += $(FATE_EXTERN)
>> diff --git a/tests/api/Makefile b/tests/api/Makefile
>> index c96e636756..a2cb06a729 100644
>> --- a/tests/api/Makefile
>> +++ b/tests/api/Makefile
>> @@ -1,7 +1,7 @@
>>   APITESTPROGS-$(call ENCDEC, FLAC, FLAC) += api-flac
>>   APITESTPROGS-$(call DEMDEC, H264, H264) += api-h264
>>   APITESTPROGS-$(call DEMDEC, H264, H264) += api-h264-slice
>> -APITESTPROGS-yes += api-seek
>> +APITESTPROGS-yes += api-seek api-dump-stream-meta
>>   APITESTPROGS-$(call DEMDEC, H263, H263) += api-band
>>   APITESTPROGS-$(HAVE_THREADS) += api-threadmessage
>>   APITESTPROGS += $(APITESTPROGS-yes)
>> diff --git a/tests/api/api-dump-stream-meta-test.c b/tests/api/api-dump-stream-meta-test.c
>> new file mode 100644
>> index 0000000000..bbfbd1f30b
>> --- /dev/null
>> +++ b/tests/api/api-dump-stream-meta-test.c
>> @@ -0,0 +1,177 @@
>> +/*
>> + * Copyright (c) 2025 Romain Beauxis
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a copy
>> + * of this software and associated documentation files (the "Software"), to deal
>> + * in the Software without restriction, including without limitation the rights
>> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
>> + * copies of the Software, and to permit persons to whom the Software is
>> + * furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
>> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
>> + * THE SOFTWARE.
>> + */
>> +
>> +/**
>> + * Dump stream metadata
>> + */
>> +
>> +#include "libavcodec/avcodec.h"
>> +#include "libavformat/avformat.h"
>> +#include "libavutil/timestamp.h"
>> +
>> +static int dump_stream_meta(const char *input_filename) {
>> +    const AVCodec *codec = NULL;
>> +    AVPacket *pkt = NULL;
>> +    AVFrame *fr = NULL;
>> +    AVFormatContext *fmt_ctx = NULL;
>> +    AVCodecContext *ctx = NULL;
>> +    AVCodecParameters *origin_par = NULL;
>> +    AVStream *st;
>> +    int stream_idx = 0;
>> +    int result;
>> +    char *metadata;
>> +
>> +    result = avformat_open_input(&fmt_ctx, input_filename, NULL, NULL);
>> +    if (result < 0) {
>> +        av_log(NULL, AV_LOG_ERROR, "Can't open file\n");
>> +        return result;
>> +    }
>> +
>> +    result = avformat_find_stream_info(fmt_ctx, NULL);
>> +    if (result < 0) {
>> +        av_log(NULL, AV_LOG_ERROR, "Can't get stream info\n");
>> +        goto end;
>> +    }
>> +
>> +    if (fmt_ctx->nb_streams > 1) {
>> +        av_log(NULL, AV_LOG_ERROR, "More than one stream found in input!\n");
>> +        goto end;
>> +    }
>> +
>> +    origin_par = fmt_ctx->streams[stream_idx]->codecpar;
>> +    st = fmt_ctx->streams[stream_idx];
>> +
>> +    result = av_dict_get_string(st->metadata, &metadata, '=', ':');
>> +    if (result < 0)
>> +        goto end;
>> +
>> +    printf("Stream ID: %d, codec name: %s, metadata: %s\n", stream_idx,
>> +           avcodec_get_name(origin_par->codec_id),
>> +           strlen(metadata) ? metadata : "N/A");
>> +
>> +    codec = avcodec_find_decoder(origin_par->codec_id);
>> +    if (!codec) {
>> +        av_log(NULL, AV_LOG_ERROR, "Can't find decoder\n");
>> +        result = AVERROR_DECODER_NOT_FOUND;
>> +        goto end;
>> +    }
>> +
>> +    ctx = avcodec_alloc_context3(codec);
>> +    if (!ctx) {
>> +        av_log(NULL, AV_LOG_ERROR, "Can't allocate decoder context\n");
>> +        result = AVERROR(ENOMEM);
>> +        goto end;
>> +    }
>> +
>> +    result = avcodec_parameters_to_context(ctx, origin_par);
>> +    if (result) {
>> +        av_log(NULL, AV_LOG_ERROR, "Can't copy decoder context\n");
>> +        goto end;
>> +    }
>> +
>> +    result = avcodec_open2(ctx, codec, NULL);
>> +    if (result < 0) {
>> +        av_log(ctx, AV_LOG_ERROR, "Can't open decoder\n");
>> +        goto end;
>> +    }
>> +
>> +    pkt = av_packet_alloc();
>> +    if (!pkt) {
>> +        av_log(NULL, AV_LOG_ERROR, "Cannot allocate packet\n");
>> +        result = AVERROR(ENOMEM);
>> +        goto end;
>> +    }
>> +
>> +    fr = av_frame_alloc();
>> +    if (!fr) {
>> +        av_log(NULL, AV_LOG_ERROR, "Can't allocate frame\n");
>> +        result = AVERROR(ENOMEM);
>> +        goto end;
>> +    }
>> +
>> +    for (;;) {
>> +        result = av_read_frame(fmt_ctx, pkt);
>> +        if (result)
>> +            goto end;
>> +
>> +        if (pkt->stream_index != stream_idx) {
>> +            av_packet_unref(pkt);
>> +            continue;
>> +        }
>> +
>> +        printf("Stream ID: %d, packet PTS: %s, packet DTS: %s\n",
>> +               pkt->stream_index, av_ts2str(pkt->pts), av_ts2str(pkt->dts));
>> +
>> +        if (st->event_flags & AVSTREAM_EVENT_FLAG_METADATA_UPDATED) {
>> +            result = av_dict_get_string(st->metadata, &metadata, '=', ':');
>> +            if (result < 0)
>> +                goto end;
>> +
>> +            printf("Stream ID: %d, new metadata: %s\n", pkt->stream_index,
>> +                   strlen(metadata) ? metadata : "N/A");
>> +
>> +            st->event_flags &= ~AVSTREAM_EVENT_FLAG_METADATA_UPDATED;
>> +        }
>> +
> 
>> +        result = avcodec_send_packet(ctx, pkt);
>> +        av_packet_unref(pkt);
>> +
>> +        if (result < 0)
>> +            goto end;
>> +
>> +        result = avcodec_receive_frame(ctx, fr);
>> +        if (result == AVERROR_EOF) {
>> +            result = 0;
>> +            goto end;
>> +        }
>> +
>> +        if (result == AVERROR(EAGAIN))
>> +            continue;
> 
> This code is not what the API docs suggest.
> 
> avcodec_receive_frame() should be called in a loop
> 
> there is not a guranteed 1:1 relation between packets and frames
> Even if thats the case most of the time
> 
> Or is this tool only supposed to work with some specific types
> of files ? (if so this should be documented)

I think for a test it's fine.
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